Bill Murray cheers on the Xavier basketball team's upset win over Arizona

The actor has been to every one of Xavier's tournament games.

ByABC News
March 24, 2017, 11:49 AM

— -- Bill Murray just proved he's the biggest sports fan ever.

The star was seen wildly cheering on No. 11-seed Xavier University in the team's victory over No. 2-seed University of Arizona in Thursday's NCAA tournament matchup.

Murray's son Luke Murray is in his second year as an assistant coach for Xavier's basketball team.

When the team pulled off the shocking 73-71 win over Arizona, Murray went crazy in the stands, high-fiving those around him and rubbing the head of Sister Rose Ann Fleming, the now-famous 77-year-old nun who makes sure all of Xavier's student-athletes meet the school's academic standards.

Murray, 66, hasn't missed a single tournament game, which has some suggesting he could be behind the team's winning streak.

"Tons of credit to Bill Murray," "Entourage" actor Jerry Ferrara tweeted after the win.

Murray is having a stellar sports year. Not only is his son's team on a roll, but last year, his favorite major league baseball team, the Chicago Cubs, clinched the World Series title for the first time in 108 years.

Even NBA star and fellow Chicago native Dwayne Wade had to acknowledge the "power of Bill Murray."

You can bet the actor will be in the stands when Xavier takes on No. 1-seed Gonzaga on Saturday for a chance to go to the Final Four.