Then a big mistake and a controversial rule took what looked like sure points off the board and instead resulted in a turnover. Fortunately for the Chiefs, they overcame it in a 27-24 win to advance to the AFC championship game.
With Kansas City leading 24-20 early in the fourth quarter, the Chiefs sniffed out a fake punt and took over possession in Buffalo territory. A 32-yard Isaiah Pacheco run then set the Chiefs up with first-and-goal at the 3-yard line.
From there, Patrick Mahomes looked to Mecole Hardman on a shovel pass near the goal line. But Hardman didn't find the end zone. He fumbled as he was tackled in the field of play, and the ball went through the end zone.
Officials initially called him down on the field, but replay confirmed that Hardman fumbled the ball.
Instead of extending their lead to 34-24 with a touchdown, the Chiefs turned the ball over at a critical juncture of the game. The Bills took over at the 20-yard line because a fumble through the end zone counts as a touchback. It's a rule steeped in controversy, as the defending team takes over without actually recovering the ball.
The fumble was the second of the day for Hardman. The Chiefs recovered the first, but they weren't so fortunate on his second.
Kansas City's defense held the rest of the way, though. The Bills wouldn't score again, as Tyler Bass' would-be game-tying 44-yard field goal sailed wide right with less than two minutes remaining in the game, and the Chiefs advanced.