Arkansas Coach Eric Musselman Parties Shirtless After Upset Win Over #1 Auburn

Eric Musselman is a man of his word -- the Razorbacks head coach partied shirtless after a HUGE upset win over #1-ranked Auburn on Tuesday night ... and it was epic!!

Here's the deal -- Muss met with a group of Arkansas students outside Bud Walton Arena in Fayetteville before the game ... and was asked if he would do a topless celebration if they knocked off the top team in the country.

Not only did coach make the promise, he kept it after Arkansas knocked off Auburn, 80-76 ... ripping his shirt off and celebrating like crazy!!

Check out the video, Muss was the center of attention, dancing, and having fun ... all while wearing a shoulder brace.

In case you were wondering, Eric is wearing that sling due to shoulder surgery he had to repair a torn rotator cuff in January.

But, somehow, the guy managed to back up his end of the deal despite the injury ... and thanked local officials for allowing him to rage peacefully with the crowd.

"Can’t thank these two enough for letting me celebrate with our fans tonight! Detective Ramirez & Sargent Robertson appreciate you both! #HogYeah," Muss wrote on Twitter.