Week 9 of the 2021 NFL season was weird. Jacksonville took down Buffalo, Dallas struggled despite getting Dak Prescott back and the 49ers were unable to secure a home victory despite playing a quarterback who had won just one game since 2014.

Here's a quick look at some of the most notable performances from a wild day of football:

Overachieving Team: New York Giants

The Giants have had a pretty good stretch in recent weeks. After knocking off the Panthers in Week 7, they lost a three-point game to the Chiefs. But there were no moral victories in their 23-16 victory over the Raiders on Sunday.

The Giants offense managed just one touchdown and averaged 4.2 yards per pass attempt, but rode to victory on the leg of Graham Gano who made three field goals. New York's defense allowed six red zone possessions, but surrendered just one touchdown and three field goals on those trips.

Danny Jones commanded a very conservative offense that attempted just three passes 10 yards beyond the line of scrimmage, although his only deep pass of the game was a 30-yard touchdown to Evan Engram.

On the flip side, the Vegas offense failed to push the ball down the field, something they've done with success throughout the season. Derek Carr was 0-3 on deep passes and was so unimpressive that the Raiders front office signed DeSean Jackson right after the game.

Underachieving Team: San Francisco 49ers

The 49ers seemed to have all the luck going into this week. Adding George Kittle back from the IR and playing a Cardinals team that was without Kyler Murray and his top two wide receivers should've been a recipe for success in Santa Clara.

Instead, the San Francisco defense was eaten alive by Colt McCoy, allowing 437 yards of offense and 31 points to a quarterback who hadn’t commanded an offense that broke the 30-point barrier since 2011. McCoy even averaged 9.4 yards per attempt, a number Murray has hit just once all season.

Perhaps the biggest gut-punch is the fact that both Kittle and Brandon Aiyuk played well, combining for 190 yards and two touchdowns on 12 catches. Despite leading the 49ers in targets, this is the first week he's caught more than four passes or gained more than 50 yards of offense.

San Francisco has now lost nine-straight home games since beating the Rams in Week 6 of last season.

Overachieving Player: Jaguars DE Josh Allen

The NFL was abuzz during the first batch of games on Sunday thanks to the Josh Allen vs Josh Allen matchup. Jacksonville entered the game as 16-point home underdogs, but the edge rusher from Kentucky made his presence felt, coming out on top over the quarterback from Wyoming.

Allen's career has been marred by injuries after a rookie season that featured 10.5 sacks and a Pro Bowl invitation. After missing 17 games in the last two seasons, Allen hasn’t missed a game this season and leads Jacksonville with 5.5 sacks.

However, Sunday represented a career day for Allen, who recorded a sack, a fumble recovery, and an interception. In fact, Allen is the first player to accomplish all three in the same game since 2018.

The Jaguars committed 12 penalties and allowed 31 points to Geno Smith a week ago, but Allen did record a pair of sacks and four tackles for loss against Seattle. After another notable performance, he seems well on his way to getting his fifth-year option picked up.

Underachieving Player: Cowboys QB Dak Prescott

The Cowboys looked every bit of a Super Bowl contender prior to Sunday. Undefeated against the spread and undefeated since their Week 1 loss to Tampa Bay, Dallas even beat the Vikings last week with Cooper Rush under center as Dak Prescott recovered from a calf injury.

Prescott's return was supposed to be a celebration for Cowboys fans, but his struggles against the Broncos without Von Miller was jarring. Prescott threw a pair of touchdowns in garbage time, but he completed just six of his 19 passes through three quarters and converted just one of eight third down opportunities.

Prescott suffered a devastating ankle injury last year and he has become an ineffective runner in 2021, averaging less than four yards per carry and setting career lows in rush attempts and yards per game. While he didn't want to blame the new calf injury for his awful performance, it's worth wondering if Prescott is back to 100%.

Bad Beat: Kansas City Chiefs -7.5

Patrick Mahomes vs Jordan Love seemed like the biggest mismatch of the weekend. Even with the former MVP struggling in recent weeks, the idea of Mahomes and company winning by just a touchdown over Love in his first NFL start seemed far-fetched.

And yet, despite the win, this might be rock bottom for the Chiefs who managed just one touchdown in Green Bay and escaped with a 13-7. Kansas City's offense scored a touchdown on their opening series, a grueling 15-play, 59-yard drive, then was held to just two field goals in their final 10 possessions.

One of those field goals was probably the most disappointing drive of the night after the Chiefs failed to cash in on a muffed punt that was recovered at the Green Bay 10-yard-line.

Kansas City is just 2-7 against the spread this season while Green Bay has covered every game since its Week 1 debacle against the Saints. The Chiefs have opened as 2.5-point road favorites over the Raiders for Week 10.