Mahomes, by comparison, finished with his worst completion percentage — 44.1% — while going 15 of 34 for 250 yards and an interception. The two-time NFL MVP had previously never finished a regular-season game completing fewer than 50% of his passes over his nine-year career.
The Bills’ defense played a major role in harassing Mahomes, who was sacked three times and hit 15 more.
“We’ve had great moments, we’ve had bad moments. We have to be more consistent as a team,” Mahomes said. “I have to be more consistent as a quarterback. And we have to be able to battle.”
The Bills (6-2) suddenly have the upper hand in the playoff seeding race by opening a 2 1/2-game edge over the Chiefs (5-4). Buffalo, however, is still chasing New England (7-2) in the AFC East standings after losing to the Patriots last month.
The Chiefs, meantime, opened a season with four or more losses through nine games for just the third time since Andy Reid took over as coach in 2013.
“Against a team like this, you have to be able to score touchdowns, not field goals,” Reid said.
Kareem Hunt and Rashee Rice scored on touchdown runs, and Harrison Butker hit both field goal attempts for the Chiefs.
The game was decided in the final 17 seconds, when Mahomes threw three straight incompletions from Buffalo’s 40. The last throw fell short of the end zone and was batted down by rookie Maxwell Hairston, who earlier intercepted Mahomes.
Bills coach Sean McDermott credited his team for coming together to pull out what stands as a signature victory. Buffalo’s previous five wins came against opponents that entered Week 9 with a combined record of 11-30, while they lost to New England and Atlanta.
“We’re not where we need to be, but I saw the team come together and when it got tough,” McDermott said, “they stood tall.”