BUFFALO, N.Y. --The list of the Buffalo Bills' missed fourth-quarter opportunities is getting lengthy. There was quarterback Josh Allen coming up just short on fourth down in a 34-31 loss to the Tennessee Titans. Of course, there was the all-around offensive failure in a 9-6 loss to Jacksonville and two weeks ago scoring zero points on consecutive red zone trips in a 14-10 loss to the New England Patriots.

Most recently, the Bills had their biggest comeback of the season after being down 21 points to the Tampa Bay Buccaneers. That, however, ended in a 33-27 overtime loss.

The Bills (7-6) started the season as top contenders for the AFC crown. In their four remaining games, including hosting the Carolina Panthers (1 p.m. ET, Fox) this Sunday, there will be little wiggle room to get things figured out.

Buffalo now has 15-1 odds to win the Super Bowl, the worst they've been since odds opened in February at Caesars Sportsbook.

Despite that, the team ranks in the top seven of ESPN’s Football Power Index for offense (No. 7), defense (No. 2) and special teams (No. 1).

How is that possible with an almost .500 record?

Closing out tight games. It has been one of Buffalo's biggest problems. The Bills went 5-1 in one-score games in 2020, finishing 13-3 and on a six-game regular-season winning streaking. This season, the team is 0-5 in one-score games.

“I think four of the five that have been one-score games, we've had the ball with the chance to win it,” coach Sean McDermott said. “And really offensive football, in this case, when you talk about execution is what it comes down to and just this past week (against the Buccaneers) in particular, just to name one, and we had chances.”

Historically, an 0-5 record in one-score games hasn’t worked out for teams looking to make the postseason. Per ESPN Stats & Info, the 1985 San Francisco 49ers (0-5) are the only team to make the playoffs after having zero wins and at least five losses in one-score games in the regular season. That team lost in the wild-card round to the New York Giants.

One big problem has been red zone woes. In wins this season, the Bills in fourth quarters have scored 10 red zone touchdowns and kicked one field goal on 17 total drives.

In losses this season, however, the Bills in fourth quarters have had eight red zone drives and scored three touchdowns and three field goals. The 37.5% red zone touchdown efficiency in those situations is 31st in the league.

“I think it’s execution and situational football,” Allen said. “Red zone, for example, we’ve got to be better in that aspect, and again, there’s a lot of shoulda, coulda, wouldas in our season this year, and a couple plays go our way instead of the other way, talk might be a little different. But again, that’s the ebbs and flows of the game of football."

Overall in 2021, the Bills are 18th in red zone touchdown percentage (58.9%). Last year, the team ranked 13th (61.8%) in the same category. Not being able to run the ball successfully (Bills running backs rank 26th in the league in rushing yards per game) has played a role in the lack of late-game success. The offensive line has also suffered from not having continuity, leading to Allen getting sacked or hit while throwing in the red zone 16 times during fourth quarters -- seven more than any other quarterback

Allen's performance has been mixed in the red zone, completing 56.5% of his passes compared to 63.1% last year. One thing that has continued is the quarterback not turning the ball over in that area, with only one red zone interception this year, the first of his career.

“It’s obvious as far as executing at a high level in the red zone,” wide receiver Stefon Diggs said. “Last year we didn’t have too many red zone problems. We were scoring a lot of points routinely. Things kind of seemed like they were easy, but it wasn’t easy. We were just making it happen. So this year when you’re hitting a little bit of a roadblock and you’re not executing or having things happen in the red zone that gets you off schedule, that’ll put a little damper on it.”

Keeping drives alive late in games has also been part of the problem with the Bills converting 33% of fourth-down attempts in fourth quarters (tied for 22nd) this season.

“It's just the familiar topic of shooting ourselves in the foot at opportune times,” center Mitch Morse said after the loss to New England.

The late-game issues fall on the defense and special teams at times, too. The defense gave up the walk-off touchdown throw from Bucs quarterback Tom Brady and the special teams gave up a blocked punt to the Steelers in Week 1.

But the opportunities have been there for an offense that relies too much on Allen, who is battling a foot injury this week. Chances to win tight games are running out.

“That's an area we're working on, guys and [offensive coordinator Brian Daboll] to continue to put the guys in position,” McDermott said. “And then we've got to get the execution level higher in those moments, but I really love the drives we've put together with the ball in those situations and now we've got to finish those drives.”