Bills are favored Sunday, but Chiefs with Patrick Mahomes are 11-3 as underdogs

The Bills are favored to beat the undefeated Chiefs on Sunday, but if we know anything about Patrick Mahomes, it's that betting against him is risky.

Kansas City is a two-point underdog at Buffalo, making Sunday's game the 15th time the Chiefs have been underdogs with Mahomes as a starter. In those 15 games, the Chiefs are 11-3 straight up and 12-1-1 against the spread.

Mahomes’ .786 winning percentage as an underdog is almost as good as his career .798 winning percentage as a favorite.

Sunday is the second time this season the Chiefs have been underdogs: The 49ers were 1.5-point favorites in San Francisco in Week Seven, but the Chiefs won 28-18.

Mahomes’ strong record as an underdog began in the first start of his NFL career, when the Chiefs started him in place of Alex Smith for a meaningless game in the 2017 season finale. The Broncos were favored by 3 points over the Chiefs that day, but Mahomes led the Chiefs to a 27-24 win.

When Mahomes became the Chiefs’ starter in 2018, it took the point spreads some time to adjust to how good he was, and the Chiefs were underdogs in both Week One and Week Two, winning both games outright. They were also 3.5-point underdogs in Week Six against the Patriots, losing the game by 3 but winning against the spread, and 3-point underdogs in Week 11 against the Rams, losing by 3 and pushing against the spread.

In 2019 Mahomes was only an underdog once, by 3 points against the Patriots, but he led the Chiefs to a 7-point win. In 2020 Mahomes was again only an underdog once, by 3.5 against the Ravens, and he led them to a 14-point win. In 2021 Mahomes was never an underdog.

In 2022 Mahomes was an underdog twice: As a 1-point underdog in Tampa Bay, he led Kansas City to a 10-point win. But as a 2.5-point underdog in Buffalo, the Chiefs lost by 4. That loss at Buffalo was the only time in Mahomes’ career that a bet on him as an underdog was a losing bet, and may give Bills bettors some confidence heading into Sunday. The Chiefs were also 1-point underdogs against the Eagles in the Super Bowl at the end of that season, but Mahomes led them to a 3-point win.

Mahomes was never an underdog during the 2023 regular season, but the Chiefs were underdogs in three playoff games: Against the Bills in the divisional round, against the Ravens in the AFC Championship, and against the 49ers in the Super Bowl. Mahomes led them to wins in all three games.

After Sunday, it's highly unlikely that Mahomes will be an underdog again this regular season. Bettors don't get many opportunities to get points with Mahomes. And when they get those opportunities, they usually regret passing them up.