BUFFALO, N.Y. -- These are not the same Buffalo Bills that failed to make the NFL playoffs in 17 straight seasons; if you let them tell it, they are not even the same Buffalo Bills who won their first AFC East title since 1995 and reached the conference championship game last season.

Under coach Sean McDermott, the Bills have built an identity on proving their doubters wrong -- which was an easy sell to a team full of players who had been cut or traded and coaches who had been fired or looked over.

But who is doubting the Bills in 2021?

Only the most staunch contrarians have been skeptical of quarterback Josh Allen's ability to replicate last season's MVP runner-up performance, and Buffalo is the betting favorite to win its second straight division championship. The Bills have the third-best odds to win Super Bowl LVI, trailing only last season's participants -- the Kansas City Chiefs and Tampa Bay Buccaneers.

But the transition from underdog to favorite has not occurred within the confines of One Bills Drive. Not with so many boxes left unchecked last season.

"Our guys understand that doing something once doesn't make you a great team," Bills general manager Brandon Beane said. "Once you're lucky, twice you're good. If you want to be a consistent contender, you got to back it up. And so, we talked here last year about a wanting to win the division, so we can host [playoff] games here. And not only did we get to host one, we hosted two.

"As good as last year was, we still didn't meet some standards that we want to get to. So, until you win it, in my mind, we're still hunting. Will people be hunting us? Yes, starting with our division. ... Our guys play with a chip, I think it starts with Sean. He does a great job. He coaches with a chip, he walks around the halls with a chip and our guys feel that."

It's easy for McDermott to stay grounded, because he's experienced just about everything in this league except for a Super Bowl victory. He lost one as an assistant with the Carolina Panthers, who went 15-1 in 2015 but were beaten by quarterback Peyton Manning and the Denver Broncos in Super Bowl 50.

Carolina went 6-10 the following season, but McDermott has yet to experience a decline like that in Buffalo. Apart from a one-game drop in 2018, the Bills have improved their record each year under him. Doing so this season after winning 13 games in 2020 would be an impressive feat.

"One of the hardest things to do is to sustain success," McDermott said. "I've been around it. I've seen it. You see it not only from the teams that I've been a part of and I've learned from, but other teams. That's the way the NFL is built, is for parity. One year a team's up, next year they're down. So that's been a message since really a month after the season.

"You've got to have enough self-awareness to manage yourself. If getting noticed was the goal, then maybe we accomplished that. [But] this is a new season. This is a new team, as I've said countless times. We've got to respect the process and remain humble and hungry because if you don't, this league gets you, it gets on you fast."

That message originates through McDermott but amplifies through Allen, the Bills' $258 million quarterback who signed a six-year extension this offseason.

Allen set single-season franchise records in several passing categories last season, when he threw for 4,544 yards and accounted for 45 TDs (37 passing, eight rushing). However, he did not play up to those standards in the loss to the Chiefs in the AFC Championship Game (28 for 48, 287 yards, two TD passes, one INT); neither did his teammates.

In fact, it's because of that performance the Bills entered this offseason with a sense of urgency, not complacency.

"I know a lot of guys have that sour taste still, and it's pushing them and driving them," Allen said. "Personally, me, that's how I feel ... we didn't do enough to get the job done last year, so let's find a way to be better this year and attack it that way.

"I have the same mindset and same mentality of [having a] chip on my shoulder. I was in junior college not too long ago. So to be sitting where I am, actually it's a great feeling. But ... the name of the game is winning championships. We won't stop until we're there, whether it's working on the field or in the weight room and in the meeting rooms, just trying to be the best that we can be and give ourselves a chance."