FOXBORO — Nine years ago this month, Patriots quarterback Tom Brady posted the first comeback win of his professional career against the San Diego Chargers, leading New England back from a 10-point deficit with just under nine minutes left for a 29-26 overtime victory.

It was just his second career win as a starter, and was the first real indication for many people outside the Patriots’ inner circle that Brady was going to be more than a guy who was expected to keep Drew Bledsoe’s seat warm until the veteran returned.

“Never a doubt, huh?” Brady asked with a small smile after the game.

Over the course of those nine years, Brady has grown from unknown into an NFL icon. He has led the franchise to four Super Bowl appearances and three Super Bowl wins, and was ranked No. 21 on the league’s list of the 100 greatest players in NFL history. He has amassed a ton of milestones: At 101-31, his record as a starter is the best of any quarterback in the Super Bowl Era, and was the fastest quarterback to 100 career wins in that same span. He has the sixth-best quarterback rating in NFL history, and was one of the fastest quarterbacks in league history to 200 touchdowns.

But Brady’s effect goes beyond numbers. In the nine years since that rather gloomy, overcast day in Foxboro, his impact on the franchise is seen in the little things behind the scenes. While the on-field performance is undeniable, teammates and friends say it is his work in the locker room, his interaction with other players and coaches and his sense of team that make him a singularly unique individual.

With that in mind, as he prepares to face the Chargers again on Sunday, we asked eight people — current and former teammates, Hall of Famers, coaches, analysts, former MVPs and other Super Bowl champions — one question: What makes Tom Brady great?

Coach Bill Belichick. With a 101-31 record together, they have the best winning percentage among a head coach and starting quarterback since the 1970 merger: “There’s no quarterback I’d rather have than Tom Brady. He does a great job for us in all phases of the game. … I think our goals are the same and I think, generally speaking, we have a similar way of approaching [and] achieving those goals. I think that works well together. I certainly enjoy that. In my association with Tom, those things that he brings, I believe in. And I think he believes in some of the things that I believe in, so that helps.”

Christian Fauria, two-time Super Bowl champion and teammate, 2002-2005. Fauria says the Brady/Joe Montana comparison is an apt one, but not because of their play on the field: “I heard a story about Joe Montana and how the guys were talking about how he was one of the greatest quarterbacks ever to play the game. They were talking about him in training camp. A lot of times, teams are just very cliquey. And they were talking about how [Montana] would sit with the offensive linemen, the defensive linemen, the black guys, the white guys. He just kind of integrated himself into every atmosphere or clique that he could. Not because he was trying to do it or be buddies, but because that was who he was. That’s the same thing with Tom.

“You sit down with him, you have his full attention. That’s who he is. He’s actually interested, he cares, and he’s into it. There’s no highbrow, there’s no, ‘I’m better than you.’ When guys are trying to come up to his level, he has an ability to come to your level. Which isn’t a bad thing. He’s Tom Brady. He’s at the highest level you can get. And that is what you hear everybody say about him. Even the guys who come over who are brand new: ‘He’s a great guy.’ That’s not BS. That’s real. He’s a good guy. He’s a normal guy. He just happens to be rolling at a high, high level. Which is great. ‘Let me piggyback on you. Where are we going? What club are we going to?’ I was like the 10th person: ‘Yeah, I’m with him too.’”

Running back Fred Taylor, teammate, 2009-2010. Taylor lost several playoff games to Brady and the Patriots, and never understood the quarterback’s true impact until he joined the Patriots: “Tom, he’s a winner for a reason. Sometimes you sit back when you’re on the outside and say, ‘Man, these guys are just the lucky ones.’ Then you see the intensity, the passion he shows in practice. He want to be perfect on every throw, every drop back. He’s a winner for a reason, but he’s humble. You don’t get that combo quite often. He’s a true leader. That might be the most surprising thing of everything. On the other side, you’re a little bit upset, a little jealous. You envy those guys. (The Patriots) knocked us out of the playoffs twice. You sit back and think, ‘We should have had it.’ Truthfully, you go in and see they deserved it. They earn it.”

Joe Theismann, former NFL MVP and “NFL Network” analyst. Theismann believes that as an on-field signal-caller, Brady is the best the league has ever seen: “I believed that Joe Montana was the greatest quarterback to play the game. I think that Tom Brady is now. I think he’s the best quarterback who has ever played the game of football. What makes him special in my mind is that he and Peyton [Manning] have equal aptitudes — they are equally smart, they understand the offense, they know what they want to do, they prepare endlessly. All of the qualities you look for in someone who is going to be special.

“But I think Tom throws the football better than anybody in football. It’s a tighter spiral. He plays in outdoor conditions, not indoor conditions. Sixteen games, he could be in absolute garbage. Every stadium is an outdoor stadium in his division. When you’re in a dome environment, it’s a different thing. Peyton’s ball has a little bit of ‘ears’ on it from time to time. Joe’s ball had a little bit of ‘ears’ on it from time to time.

“I feel like as far as what separates him is his ability to purely throw the football. Joe Montana. Peyton Manning. The great quarterbacks like Dan Marino. John Elway. Brett Favre. You name all of them. I think the best pure thrower of the football is Tom Brady, and that’s why I give him the edge. If you were able to put those guys in a pool together, everybody is just great. They’re all Hall of Famers. They’re all special. They’re all unique. But what separates Tom from them is his ability to throw the football the way he throws it.”

Jim McMahon, two-time Super Bowl champion. McMahon said Brady has benefited from those around him: “His offensive line makes him great, for one. He’s had a pretty good offensive line over the course of his career. And that’s the key. You can’t be successful behind the center unless those guys up front do their job. When those guys do their job, you can look pretty good.”

Marcus Allen, Pro Football Hall of Famer and former NFL MVP. Allen said Brady has three key elements that make a great athlete: “I think it’s the mind, body and spirit. It’s three-dimensional. First of all, the body — I think he’s a much better athlete than people give him credit for. Intellectually, I think he understands the game much better than anybody and I think his spirit is such that he wants to be great. And in his walk and his talk, everything about him, says that with an exclamation mark. That’s what I recognize. I see it as three-dimensional. Some people have three of those elements, some people just have two. He has all three of them.”

Tight end Alge Crumpler, teammate, 2010. Crumpler has been with the Patriots for a relatively short time, but has grown close to the quarterback: “He just understands the big picture. Most quarterbacks would be happy sitting at 4-1. He’ll be happy if we do things right every single play. Every single day. He commands it out of himself and he wants to make sure it trickles down throughout our offense. Moreso the whole team, but he really wants it for the offense.

“I’ve always felt like he’s the best quarterback in the game. He’s always been my favorite quarterback. His poise, how calm he is. Just watching the way he stands in the pocket while everything is moving around him and he continues to deliver the ball on point play after play.”

Bay Area quarterbacking guru Tom Martinez. Martinez has been the one constant in Brady’s life since the quarterback was a teenager, and he continues to tutor him on a regular basis: “I think it starts with his parents. His Dad and his Mom are complete contrasts, and yet, they’re very similar. His Dad is kind of a businessman, and his Mom is very, very competitive in a very quiet way. And that’s kind of how he is. He’s not that cheerleading kind of guy. He’s a fierce, fierce, fierce competitor, in a very internal way.

“The biggest thing that I know and appreciate about him is that we started working together when he was 12 or 13, and he still, with the success and the accolades and the whole lifestyle and whole thing, obviously, he can go anywhere he wants to for help, and he still comes back after all those years and he’s very, very humble for a guy. I’ve also worked with JaMarcus Russell, and you talk about a different mental makeup in regard to excellence. Perfection and excellence. He strives, strives, strives for perfection. We’ll work on things and he’ll be off five or six inches, and that bothers him because he’s trying to be perfect.

“I think there’s not many people once they reach a certain level of excellence, they kind of shut down because now it’s time to enjoy the deal and the environment and the flamboyance and all that. With Tom, I still see that passionate desire to win and to excel and I think that peace and quiet demeanor is very relaxing to his teammates. I watch other guys, and even Peyton [Manning], he’s very fine until things don’t go well. Then, you see that expression on his face. Tom’s gotten frustrated at times too, but I think that his work ethic and his person are just different.

“People look at him and people admire him because one, he’s handsome. Two, he’s smart. Three, he carries himself well. Four, he plays well. Five, he has a gorgeous wife. I e-mailed him and told him, ‘I don’t know if you understand it — you’re standing where every man would like to be. They would love to be in your shoes in every possible way — in one way, let alone all of them together.’

“To me, he just hasn’t changed. He’s still the same young man I knew when he was younger.”