When did the Bruins turn the corner and become a top-tier NHL team? Because, like it or not, they are one of only eight teams left in the Stanley Cup Playoffs.

Boston advanced to the Eastern Conference quarterfinals for the second year in a row by finishing off the Sabres 4-2 in Game 6 Monday night at TD Garden (click here for the complete recap). After dominating the NHL last season, many pundits figured the Bruins were a lock for at least a conference semifinals appearance this year. But somewhere along the way Boston got lost, mired in a slump with an aura of melancholy surrounding the team. However, the Bruins turned it around in mid-March and have marched all the way to the second round.

It’s hard to say exactly when the team really started coming together, but the moments after a Penguins game on March 18 game — where everybody was looking for revenge on Matt Cooke for his hit on Marc Savard — would be a good start.

“Somewhere after that Pittsburgh game … and we came back after a 12-day road trip,” coach Claude Julien said. “I thought coming back from a tough trip like that, and then we had that stinker against Pittsburgh, [which] kind of gave us a jolt. And I thought we reacted from there and we got back to playing much better, and from there on in we were a pretty good team.”

The storylines are compelling. Savard’s first game back from his Grade 2 concussion will likely be Game 1 of the conference semifinals which, barring a Canadiens upset of the Capitals in Game 7 of their series Wednesday, will be at the Igloo in Pittsburgh.

But before we look ahead, let us take a minute to look back on just how the Bruins put the clamps on Buffalo.

Here is the Hat Trick:

SPECIAL TEAMS WAS THE KEY

The Sabres and Bruins were pretty well matched in the series. Buffalo had an advantage with Thomas Vanek, but it lost him in Game 2 and did not get him back until Game 6, where he scored the Sabres final goal of the season at 18:47 of the third period as Buffalo tried to keep its season alive.

Sans Vanek, it would come down to who scored on the power play. That was Boston, as it had a six man-advantage goals while not allowing a single power play strike to the Sabres through 19 chances in the series.

“We pride ourselves real hard on special teams,” Vanek said. “I think their [penalty kill] outmatched our power play. That is disappointing.”

When it came to 5-on-5 play, Buffalo was a distinctly better team than Boston. For the series they held a 13 to 8 edge in even-strength goals.

“If you look at it, they scored two power play goals and we didn’t get any. Our penalty killing, which had really been our backbone the whole year, we made some mistakes in this series, some mistakes that we’d like to have back. Overall, it just wasn’t good enough and that is the bottom line,” Sabres coach Lindy Ruff said. “They definitely had the edge and it made the difference in the series.”

In a lot of ways, the Sabres outplayed the Bruins for most of the series. No specific area outside of special teams had a glaring weakness, and they held a lead in every game until the final one. It really came down to a matter of not finishing off opportunities the way the Bruins did.

“I don’t think we played poorly in this building. I think for the most part, our special teams didn’t get the job done in here. They scored a lot of power play goals and killed any big penalty. They were able to kill it and stop of from getting momentum,” forward Michael Grier said. “We had a good chance to go up 2-0 in the series and we didn’t take advantage of those things. In a playoff series, those things come back to haunt you.”

The Bruins scored the opening goal of Monday’s game for the first time in the series on the power play in the first period when David Krejci tipped a shot off the stick of Mark Recchi from the right wing that beat goaltender Ryan Miller at 13:39. Krejci and Recchi struck again in the early in the second period on a 4-on-3 power play when the Czech forward found his British Columbian brethren on Miller’s doorstep with a pass through the slot that Recchi banged home at 1:01.

“Yeah, it was great,” Recchi said on the connection between him and Krejci. “He made a great tip on the first one. He got himself in great position and on the second one he made a heck of a pass to me and I had a wide-open net. He played a heck of a game. He is a great player and when he plays like that, when our centermen play like that, we are going to be tough to beat.”

MIRO THE HERO

Miroslav Satan has shown a knack for big goals down the stretch for Boston. He scored the game-winning goals in the double overtime Game 4 in Boston, and then the series clincher in Game 6.

The play was set up after Satan had circled Miller’s crease with the puck on his stick, waiting for the goaltender to make a move that the forward could break down and put it in the net. But Miller is a Vezina Trophy finalist for a reason, and he shut the door when Satan finally did shoot.

The rebound was kicked back out and cycled and ended up on the stick of defenseman Dennis Wideman, who rushed down the right wing and centered it back through the crease that had just been cleared of Sabres by Milan Lucic. Satan got the backdoor and the game was won at 14:49 of the third.

“He opened up that pass for me,” Satan said of Lucic. “There were several things going on at once, [Lucic] open up the lane and [Wideman] made a perfect pass with his head up and I was able to finish it.

It was the second time in the series where Miller shut down Satan, only for the forward to come back and score on the next series of plays.

“Yeah, maybe I just try to make him feel comfortable the first time,” Satan said. “I don’t know — he is a good goalie so you can’t score all the time on him.”

It took a while for Satan to get going after he signed with the Bruins, but he’s been a key player for them down the stretch. Satan was a guy who was sitting on his couch as an unsigned free agent on New Year’s Day, and now he is a key player for an team making a surprising playoff run.

“There were two reasons I wanted to sign for half the year,” Satan said. “It was the Olympics and the playoffs. It’s fun after last year, and what I have been through going all the way. It is fun to be in the playoffs again, and this team maybe lost out on a big opportunity last year, so we will see what happens this year. We will enjoy it while we are here.”

LUCIC AND HIS PROPENSITY FOR BIG MOMENTS

Lucic had not had a great series before Game 6. He had a plus/minus ratio of -2 and 13 penalty minutes to his credit, but that was about it for his stat line. In the final game of the series, though, he was a difference maker

“Our passion to stick with it and be determined and, you know, make big plays in the third really helped us out and came through to win this series,” Lucic said.

Lucic’s disappointing play and corresponding lack of production from Marco Sturm caused Julien to switch the lines as of practice on Sunday, switching Lucic to play with Krejci and Satan and putting Sturm back with Patrice Bergeron and Recchi. The moved paid off for at least a game for the Bruins.

“Yeah, he played great throughout the series. And when we made that little change on the left side with [Sturm] and [Lucic] and they switched places, it seemed like it helped both lines. So I think that was a great move from the coaches,” Satan said.

Lucic set Krejci up for the center’s second goal of the game at 7:18 of the third period when he retrieved the puck after it was rimmed by Satan behind Miller’s net. Lucic was strong on the puck with A-frame protection, and battled it away from defenseman Tyler Myers and center Derek Roy to backhand it to Krejci in front of the net.

“I think he’s been playing very well,” Krejci said. “Even in the first period, he won so many battles for me. On my second goal, you know, it was basically all his work so I am very happy with the way he played, and I look for him to do the same thing in the second round.”

The difference in the second round is that Lucic will probably be doing his cosa nostra thing and providing protection when his old linemate Savard returns to the lineup.

“It is great, you know. I was able to take some confidence out of this and elevate my game, moreso in this game than the previous five,” Lucic said. “It is a great feeling and it was great that I was able to contribute but I can’t look back now, I can’t be satisfied. I got to try and keep raising my game to another level because no matter who we play it is going to be a tough series.”