When chair umpire Mariana Alves assessed the penalty, Mike Bryan objected.
"What did I do? Just tell me what I did, real quick," Mike Bryan said.
“The gesture that you did,” Alves said. “You did it to the line umpire and did it to me. You did with your racket like it was a gun. I don’t think that was appropriate.”
According to U.S. Tennis Association spokesman Brendan McIntyre, "The gesture warranted that amount.''
The fine came in the aftermath of a mass shooting Saturday in the Odessa-Midland area of west Texas.
Mike Bryan, 41, a six-time champion in men’s doubles at the Open, apologized in a statement.
“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,” Mike Bryan said.
The Bryans won the match; 4-6, 7-5, 6-3, early Sunday morning.