KEY BISCAYNE, Fla. — The Miami Open began with the prize-money debate still roaring, and Andy Murray was a frontrunner for equality. But he never meant that he wanted to play with the same tennis balls that women use.

The men’s balls are heavier and larger than women’s balls. Apparently the wrong ball was mistakenly pulled out of a flowerbed and used for play.

Murray got broken at 2-2 in the second set against Denis Istomin. As he was serving during that game, he discovered that a WTA ball was mixed into the normal ATP balls, and proceeded to flip out during the changeover.

“It’s not right. Do you know how different the balls are?” he said to umpire Mohamed Lahyani. Fans weren’t clued in on what was going on, so Murray was also miffed that people could have assumed he was just stalling intentionally.

“I saw it just before I was about to serve. It's quite off-putting because I just missed two balls long,” he said after the match. “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.”

Other than remove the WTA ball, Lahyani couldn’t do anything to resolve the mistake. But no harm, no foul as Murray went on to win the match, 6-3, 7-5.