FOXBORO -- Just after 4 o’clock on Sunday afternoon, everything changed for the Patriots.

For New England, which had just disposed of a feisty Bills team in the regular-season finale for both teams, 49-21 (click here for the full recap), the switch was flipped from the regular season to the postseason. And thanks to their win over Buffalo, the Patriots will enter the playoffs with the No. 1 seed in the AFC and home-field throughout.

It has been a strange season in the AFC. Unlike the NFC, where Green Bay and New Orleans (and to a lesser extent, San Francisco) have clearly emerged as the class of the conference, there’s no such situation in the AFC. No one has managed to consistently distance themselves from the rest of the pack, as on separate occasions the Ravens, Patriots, Steelers and Texans have all looked like the best team in the AFC.

But as the playoffs loom, after a regular season when the New England defense was historically bad, the Patriots still might just stand out as the least-flawed group in the conference. Consider the rest of the field:

• The Ravens were the team that turned out the lights on the 2009 Patriots with a shocking playoff win at Gillette. But this year’s Baltimore team is wildly inconsistent away from home, with a 4-4 record on the road, including ugly losses at Jacksonville, Seattle and San Diego. And while Ray Rice still is one of the best running backs in the league, the Baltimore passing game is sluggish at best.

• The Steelers? How about a hobbled Ben Roethlisberger and a banged up Pittsburgh offensive line, one that’s yielded 40 sacks (ninth in the league)? As bad as the Patriots played against the Steelers in Pittsburgh in October (an afternoon when New England set a season-low in rushing and passing yards), they still nearly came away with the win.

• The Texans have a stout defense, but they have third-stringer T.J. Yates under center, and he’s backed up by Jake Delhomme. (Yeah, that Jake Delhomme.) Oh, and Houston is on an ugly losing streak entering the postseason, having dropped three straight to teams with a combined record of 17-31.

• Then there’s the Bengals and Broncos, two teams that managed to sneak in under the wire on the final day of the regular season. Denver lost three straight down the stretch and needed some help to back in, while Cincinnati certainly doesn’t inspire much fear, especially on the road.

This is not to suggest that the Patriots are without warts of their own. Over the course of the regular season, they did not beat a team with a record better than 8-8. The defense hardly inspires confidence when it comes to stopping the run or the pass, and is historically bad -- New England set a new record for most yards passing allowed, 4,727. (The previous mark of 4,541 was set by the Falcons in 1995.) There are questions about the long-term health for some key members of the offensive line. And the Patriots are on a three-game playoff skid, with the last two defeats coming at Gillette Stadium.

But a world-class offense with one of the best quarterback in the NFL (and two of the best pass catchers in the league in Wes Welker and Rob Gronkowski) can paper over a host of defensive deficiencies. The defense is on a roll when it comes to well-timed turnovers (more on that later) and is also getting one of its best defensive players back as the postseason begins in safety Patrick Chung. And maybe the most important thing of all is the fact that the Pats won’t have to travel. Instead of worrying about the turf in Pittsburgh or the noise in Baltimore, they’ll be home throughout, in their own facility and in their own beds. That’s why Sunday was so important: This team has so little margin for error, it can’t afford to miss out on an opportunity like the chance to play at home for the entire month of January.

Quarterback Tom Brady, who went 23-for-35 for 338 yards and three touchdowns with one interception -- and finished the regular season with the second-most yards passing in NFL history, 5,235, after throwing for 338 -- believes the No. 1 seed will only go so far.

“It depends how well we play,” he said. “I think [what’s] going to be the determining factor on whether we win or lose is how well we execute. It’s great playing at home. It’s great to have a bye. But I think we have to concentrate here this week on what we need to do to play our best football in a couple of weeks.”

The Patriots’ last postseason win came against the Chargers in the AFC championship game in January 2008 that sent New England to Super Bowl XLII. Now, almost four years later, thanks to a weakened AFC and a world-class offense, the Patriots appear to be equipped to once again win in January.

Here are nine other things we learned Sunday at Gillette Stadium.

AARON HERNANDEZ HAS EMERGED FROM THE SHADOW OF ROB GRONKOWSKI

It’s clear that Hernandez will be a bigger focus of the New England passing game in the postseason. Opposing defenses will likely focus their efforts on trying to slow down Welker and Gronkowski, and both got knocked around pretty good on Sunday, Welker in particular (he took a nasty shot to the ribs from Buffalo’s Marcell Dareus and was sidelined for a few plays). Meanwhile, with an offensive line hit hard by injury, Gronkowski spent a sizable portion of the first half working as an extra blocker. (He had three catches for 26 yards in the first half.) He did finish with eight receptions for 108 yards and two touchdowns, but much of that work came down the stretch with the game sufficiently out of reach and the Patriots trying to get him the record. In their place, Aaron Hernandez stepped up and had a big afternoon, finishing with seven catches for a game-high 138 yards and a touchdown. His best moment came in the fourth quarter, when his 44-yard reception set up a New England touchdown that made it a two-score game. After a dip in production in the middle of the season (a stretch where Welker and Gronkowski carried the passing game), he’s starting to emerge as a threat that’s every bit as dangerous as Gronkowski.

By the numbers: Gronkowski (90) and Hernandez (79) combined for 169 receptions in 2011, the most by a pair of tight end in the same season in NFL history. Jason Witten (94) and Martellus Bennett (33) combined for 127 in 2010 with Dallas for the second most.

Money quote: “You try to play to the strengths of your offense and play to the strengths of the guys that you have. There’s no doubt this year that our pass catchers are the biggest strength of our offense. To get the ball to those guys with room to run and space is – whether it’s [Gronkowski] or Wes or Deion [Branch] or Aaron. Aaron has been huge here. All those guys are threats, and you just try to continue to find ways to get them the ball in space.” -- Brady on the varied options in the New England passing game

WELL-TIMED TURNOVERS CONTINUE TO SAVE THE PATRIOTS DEFENSE

For the fourth consecutive week, the Patriots were able to turn well-timed turnovers into points. New England had four interceptions on the afternoon, with two from Sterling Moore and one each from Devin McCourty, but it was the first Moore interception and the McCourty pick that turned the momentum of the game around. With just over four minutes left in the third quarter and the Bills clinging to a 21-20 lead. With Buffalo facing a second and 2 at their own 28, Bills quarterback Ryan Fitzpatrick dropped back to pass and looked left. He flung a short pass out there, meant for wide receiver Ruvell Martin. The ball was picked off by Moore, who took it back to the Buffalo 25. New England then followed that up with a five-play, 25-yard drive that ended when Tom Brady hit Rob Gronkowski on a perfectly run route from 17 yards out. A two-point conversion made it 28-21, Patriots. On Buffalo’s next drive, Fitzpatrick managed to guide the Bills to the New England 32-yard line, and with a first and 10, Fitzpatrick went deep down the field for C.J. Spiller. This one was picked off by Devin McCourty, the second straight game where the Rutgers product was able to come away with a pick. Two plays later, Green-Ellis rumbled in from three yards out to give New England a 35-21 lead with 11:20 remaining in the game.

By the numbers: The Patriots were able to come away with four interceptions against the Bills, a season high. They finished the regular season with 23 interceptions, the third most of the Bill Belichick era in New England. (The Patriots had 29 in 2003 and 25 last season.)

Money quote: “The ball got tipped, and I just remember in college, my defensive backs coach always used to say, ‘When you’re in the middle of the field, you can make a lot of interceptions on tipped balls.’ Once it was in the air, I was just trying to track it down and get to it.” -- McCourty on his pick

DESPITE SCORING 49 UNANSWERED POINTS AGAINST THE BILLS, THE PATRIOTS ARE CONCERNED ABOUT SLOW STARTS

As has been the case over most of the second half of the season, the Patriots got off to a slow start Sunday against the Bills, failing to put up a single point in the first quarter on the way to an early 21-0 deficit. Along the way, New England had just five yards in the first quarter while the Bills had five plays of 15 or more yards in route to gaining a total of 185. Much like they did over the previous three games, the Patriots were able to absorb the early punch, step back, diagnose the problems, make the adjustments and impose their will on their opponent. As a result, New England put up 49 consecutive points on the way to the win. Spotting an opponent a couple of touchdowns is OK if you’re facing Miami, Washington or Buffalo. That likely won’t be the case when the postseason rolls around.

By the numbers: Over the course of the 2011 season, the Patriots scored 82 points in the first quarter of action. That averages out to five points per game in the first quarter. It’s the lowest scoring quarter for New England since the Patriots offense posted 75 in the fourth quarter of the 2009 season.

Money quote: “It’s just not what we want to do. It’s not a pattern we want to fall into. It’s just not the way we want to play. ... I think everybody realizes in the playoffs, it’s not something you can do. When you see the Steelers, the Ravens, the Houston Texans, you start seeing those names and you start seeing some teams that can really put up some numbers and really play good defense. I’m talking about some really good defensive teams. You can’t afford that. You can’t afford to let that happen.” -- Brian Waters on the slow starts by the Patriots offense

PATRICK CHUNG WAS EAGER TO GET BACK ON THE FIELD

It was the return that many Patriots fans were hoping for. Safety Patrick Chung returned to action Sunday against the Bills for the first time since he suffered a foot injury in the waning moments of a Nov. 6 loss to the Giants. He announced his presence with authority -- on the fifth play of the game, Buffalo was facing a third-and-6. Bills’ quarterback Ryan Fitzpatrick looked short for wide receiver Stevie Johnson, and while Johnson made the catch, Chung delivered a big shot to the receiver to hold him short of the first-down marker. (Buffalo converted with a fake punt on fourth down.) According to ESPN Boston, he played the whole game, and the official NFL gamebook had him for seven tackles (one solo) and a quarterback hit, his second on the season.

By the numbers: Chung tied for tops on the team in tackles on Sunday, tied with linebacker Jerod Mayo and defensive end Mark Anderson.

Money quote: “It feels good to be back with my family my brothers out there and just having some fun. The first play I was definitely nervous, but after that it went away and the game just comes to you and it’s just about football. ... Sitting around waiting it kind of hurts a little bit, but now, I’m back with my guys. Once again it’s not about me we just won it’s the team. It was very important. You can’t go into the playoffs just straight into the playoffs, you have to have a warm up game to get your legs right get your footwork going and get your mind back on football and then see how it goes from there.” -- Chung on his return

THE PATRIOTS WILL CONTINUE TO USE A ROTATION AT RUNNING BACK

After leaning heavily on BenJarvus Green-Ellis to start the season, for the better part of the last month, the Patriots have started to settle into a serious rotation at running back, going with rookie Stevan Ridley more and more down the stretch. On Sunday against the Bills, Ridley got the start and finished with 15 carries for 81 yards (his second-best output of the season), while Green-Ellis had seven carries for 22 yards and a pair of touchdowns. It was the most production for Green-Ellis since the Nov. 27 win over the Eagles, when he finished with 44 yards. (He added a 53-yard reception on a smartly executed screen pass in the second half when he got an absolutely great block from Brian Waters.) I asked Green-Ellis after the game if he’s OK, considering the bumps and bruises he’s sustained over the course of the season (including a toe injury). He laughed it off, but it’s clear that one of the reasons the Patriots have started to lean on Ridley more is because Green-Ellis is physically not the same back he was when he went for 1,008 last season.

By the numbers: Green-Ellis had two touchdowns on the day, a 1-yard run in the second quarter and a 3-yard run in the fourth quarter, giving him 11 for the season. With 13 rushing touchdowns last year and 11 in 2011, he is the third running back in team history with back-to-back 10-plus touchdown seasons. In addition, the Patriots are now 22-1 (.957) when Green-Ellis has a rushing touchdown in a game. The only Patriots loss was a 2008 game at Indianapolis.

Money quote: “I don’t even really look at it like that. Whenever we’re in, whoever is in – me, Danny [Woodhead] Stevan [Ridley], Shane [Vereen], Kevin [Faulk] or [Lousaka Polite], we go out there and try to make plays for our team and make us better. It’s a team effort.” -- Green-Ellis on whether or not the Patriots not have a rotation at running back

DEVIN McCOURTY IS AN OPTION AT SAFETY

The cornerback saw a large chunk of time on Sunday against the Bills at the safety position, teaming with Chung on the back end for much of the game. He frequently served as the deep safety, and managed to look relatively comfortable in the role, finishing with five tackles (two solo) one pick and a pass defensed. He did have some bad moments early, and was frozen on a play-action pass in the first quarter that allowed Buffalo’s Derek Hagan to get deep on a costly 47-yard pass interference penalty. (At least in the early going on Sunday, the move had an affect on the rest of the New England defense, and Antwaun Molden saw time at corner because of the move and struggled in coverage -- he was the one who was flagged for the pass interference call where McCourty had issues.) McCourty’s highlight came when he came away with his second interception of the season early in the fourth quarter.

By the numbers: It was the second interception of the season for McCourty and the ninth of his career.

Money quote: “We worked with him and Patrick back there all week and thought it looked good this week in practice, so we went with it during the game. I’m sure it could be better, but I thought they gave us some things back there. James [Ihedigbo] came in a played a solid role for us, too. We got good play out of all of those guys. We had some guys step up at the corner position – Sterling [Moore] Antwaun [Molden], so that was good, too. We got a lot of snaps out of Julian [Edelman].” -- Belichick on the play of McCourty

THE PATRIOTS CARE DEEPLY ABOUT PERSONAL RECORDS

While there was some question about Brady’s ability to surpass Drew Brees and break the single-season mark for passing yards in a season, Gronkowski had a better shot at shattering the single season record for most receiving yards by a tight end -- Kellen Winslow has the mark with 1,290. (Gronkowski and Saints tight end Jimmy Graham came into the game with 1,219 and 1,213 yards, respectively.) Graham broke it first, and then Gronkowski surpassed him. The Saints put Graham back into the game late to pass Gronkowski, and it looked like the New Orleans tight end would be able to walk away with the mark. But Gronkowski caught a 22-yarder in garbage time from backup quarterback Brian Hoyer to pull it out. Gronkowski ended with 1,327 yards (on the day, he had eight catches for 108 yards and two touchdowns) while Graham finished with 1,310.

By the numbers: Gronkowski finished the season with 18 overall touchdowns (17 receiving, one rushing). His 17 touchdowns passed Curtis Martin (17 overall in 1996) for the second highest single season total in Patriots history. Randy Moss had a franchise record 23 total touchdowns in 2007.

Money quote: “Yeah, that last play I had [offensive coordinator] Billy [O’Brien] call that because I wasn’t sure exactly where he was and I though he deserved another chance to go up and try to make another play. He’s had a great year and he’s worked hard. I thought he deserved that. I’m not really sure where it stands or doesn’t stand, but we threw it up there one more time to him. He made a nice play.” -- Belichick on Gronkowski’s record-setting catch

BRIAN WATERS IS HAPPY

The veteran offensive lineman wrapped up his first full regular season with the Patriots on Sunday with a business-as-usual performance against the Bills -- going wire-to-wire at the right guard spot. While there has been plenty of shuffling along New England’s offensive line, Waters, who is signed through the 2012 season, has been a pillar at guard. He was the only member of the Patriots’ offensive line to play all 16 games at his position over the course of the 2011 season, and has been consistently graded as one of New England’s best offensive linemen over the course of the 2011 season. For a 34-year-old castoff from Kansas City, it’s been a good year, and while it’s probably still too early to commit, it sounds like he’d be open to a return in 2012, no matter what happens over the course of the postseason .

By the numbers: According to Pro Football Focus, Waters has allowed two sacks on the season. That’s the fewest of any New England offensive lineman who has played at least 800 snaps in 2011.

Money quote: “I’m happy about that. I’m happy about that. Not knowing what the situation was going to be for me as far as coming in here, but I’m excited about that. It’s definitely one of my goals to play all 16, and that happened. It’s a good feeling. Now I want to finish it out, so I definitely want to be able to play better the next football game, for sure.” -- Waters on being able to go wire-to-wire this season as New England’s right guard

STEVIE JOHNSON’S ANTICS MAY HAVE BEEN THE BEST THING TO HAPPEN TO THE PATRIOTS ON SUNDAY

The Buffalo wide receiver -- the best skill position player on the Bills roster -- displayed an extraordinary lack of good judgment on Sunday. After catching an 18-yard touchdown pass in the first quarter from Fitzpatrick, he pulled up his jersey in the back of the end zone, showing that he had “Happy New Year!!!!” scrawled on his T-shirt underneath. While the message was relatively benign, the action drew a 15-yard unsportsmanlike conduct penalty, and Buffalo coach Chan Gailey left him on the bench for the rest of the afternoon. (This wasn’t the first time he has gotten into trouble in a game in Foxboro. Johnson was also fined $10,000 for pretending to shoot off a rifle against the Patriots last year, mocking the Minutemen who celebrate a New England score.) In a game that was in doubt throughout the better part of three quarters, Buffalo really could have used its No. 1 receiver, especially when it was passing to try and get back into the game. But Johnson sat the rest of the way and watched as the New England offense rolled up 49 unanswered points on the way to the win.

By the numbers: Johnson had four catches for 40 yards to become the first Bills receiver with consecutive 1,000-yard seasons.

Money quote: “I didn’t know it was going to draw a penalty. At the end of the day, what I did was what I did, and I am going to try and bring in the New Year. Ultimately, it hurt my teammates and that is the thing that is hurting me the most. That is that it hurt my team. The coach told me that I was out of the game, He said for the rest of the game, and I have to respect his decision. He made it and that is what it is. I can’t complain about it or whine or pout. He made his decision and I am going with it. It really doesn’t matter why or how it happened. At the end of the day, what I did hurt my teammates and I have to take that, and I will.” -- Johnson on his penalty