Jannik Sinner's opponent jokingly accused him of “breaking” his racket because he played “too fast” in the semi-finals of the Shanghai Masters.

Tomas Machac fought back, serving to stay in the game while trailing the world No. 1 4-6, 4-5.

He was forced to stop play so he could change bats before serving again after the frame appeared to unravel.

The Czech star had been broken in the first set at exactly the same moment and was trying to grab a lifeline in his first ever Masters semi-final.

After losing the first point of the game, Machac suddenly sprinted to his bench and showed referee Mohamed Lahyani why he had to change his racket. “No problem,” the presiding officer said before seeing the damage and exclaiming.

Before making the change, the 30th seed wanted Sinner to see how bad it was. “Too fast. The rallies are too fast,” he said, shouting to the Italian who was waiting on the baseline.

A confused Sinner rushed over to take a look before realizing his opponent was joking.

“The racket is broken. You’re playing too fast,” Machac added before Sinner finally caught on, laughing as they both returned to the field to continue the game.

The Czech players' hilarious reaction sent the referee and commentators into a frenzy. “He helps us stay in the game in the semi-finals. That’s nice,” Barry Cowan said on commentary.

Nick Lester replied: “It's nice to have an issue that shows he's kind of embracing the moment. It wasn’t an overwhelming opportunity for him.”

After the unusual interruption, Machac was able to hold on and equalize to 5:5. But it was the last game he won as Sinner broke and won 6-4, 7-5.

With the win he is guaranteed to end the season as year-end number 1 for the first time in his career. “It's amazing, isn't it? It’s something you dream about as a kid, when you’re young, just to get to No. 1,” Sinner said.

“Now that the year is over, it's a completely new, special feeling. But that happens during a tournament, so I’m not even looking forward to it that much.”

“I know that tomorrow will be an important day, the finals are coming up. But it obviously means too much to me, and that's something I couldn't achieve without the people around me, the family and the friends, and of course that's also a big thank you to my team.”