American doubles tennis player Mike Bryan was fined $10,000 for making a gun-like gesture at the U.S. Open tournament on Saturday.

During the second-round match, playing with his twin brother Bob, Mike placed his tennis racket against his shoulder pretending to aim the handle at the chair umpire, Mariana Alves. Mike aimed his racket at Alves after the wrong call was made during a doubles match against Federico Delbonis of Argentina and Roberto Carballes Baena of Spain.

The Bryan brothers went on to win the match, but Mike received a fine of $10,000 for unsportsmanlike conduct, the highest fine given to a male tennis player during this year’s U.S. Open.

Brendan McIntrye, spokesman for USTA, stated, “The gesture warranted that amount.”

Mike said in a statement cited by the New York Times,”I apologize for any offense I may have caused. We won the point and the gesture was meant to be playful. But given the recent news and political climate I understand how my gesture could be viewed as insensitive. I promise that I will never do anything like this again.”