Andy Murray advanced to the third round at the Miami Open on Saturday, but not without a little controversy.

The World No. 2 lost his composure a bit and vented at the chair umpire after a women’s ball was introduced into the match while he was facing break point at 2-2 in the second set.

He pointed out the error (the women’s balls are marked with a red stamp and have a different type of felt that makes them livelier than the men’s) but was unsatisfied by the umpire’s response.

“That’s unbelievable. That’s one of the women’s balls. I could have just hit a shot with it,” he vented after discovering it.

Murray then lost the break point and chided the umpire again during the sideline exchange, saying “It’s not right. Do you know how different the balls are?”

According to ESPN, Murray isn’t even sure he didn’t use one of the women’s balls.

“I saw it just before I was about to serve. It’s quite off-putting because I just missed two balls long. I didn’t know if that was one of the balls I used in the last couple points. The women’s balls are very different to the men’s balls. They’re much quicker, smaller, livelier.

“Yeah, when you’re just about to serve at break point down, you know, you don’t want to be using a completely different ball. So I was just a bit frustrated with that because I didn’t know potentially if one of the points before I had used it or not.”