"WOOOOOOOOOOOOOOOOOOOOOOOOOO"
That's all that was coming from Patrick Mahomes' girlfriend, Brittany Matthews, on Sunday ... 'cause the NFL superstar's lady doubled down on her new ritual of completely losing her mind in support of the Chiefs.
Kansas City held off the Tennessee Titans to lock up the AFC Championship ... and Mahomes had his biggest fan cheering him on from the VIP suites.
The yelling was well underway before kickoff ... and somehow Brittany was able to maintain her loud levels throughout the game.
Of course, Matthews is known for being outgoing at Chiefs games ... and sometimes gets on the receiving end of heckling from other fans (like at the Patriots game).
"WE'RE GOING TO THE SUPER BOWLLLLLL" Matthews yelled, alongside Patrick's little bro, Jackson.
Now that her man's team is heading to Miami for Super Bowl LIV, we're sure Brittany's resting her vocal cords for a couple weeks to get ready.