Matthews had a message for critics who doubted her fiancée and the team all season long.
“NEVER DOUBT US,” she wrote on Twitter after the game.
She also tweeted a video showing herself spraying champagne on the Kansas City crowd in celebration following the team’s victory.
It was an epic night for Mahomes and the Chiefs as they now get set to take on the Cincinnati Bengals in hopes of making a third consecutive Super Bowl appearance.
Mahomes somehow found Tyreek Hill for a long touchdown catch and run after the Bills had gone up with less than 2 minutes remaining in overtime. After the Bills scored, Mahomes drove the Chiefs down the field to help set up a Harrison Butker field goal to put the game into overtime.
In the overtime period, Mahomes found Travis Kelce for the game-winning touchdown.
Kansas City won 42-36.
Mahomes finished 33-for-44 with 378 passing yards and three touchdown passes. He had a touchdown each to Hill, Kelce and Byron Pringle.
It will be the fourth straight year Kansas City is playing in the conference championship.