Tomas Machac left Roger Federer in stitches with the perfect response to a fan’s interruption.

The 30th seed took on world No. 1 Jannik Sinner in the Shanghai Masters semi-final on Saturday.

They had a high-profile spectator in Roger Federer watching from the front row.

But the retired tennis star’s presence was distracting, as fans showed their admiration for the 20-time Grand Slam champion whenever he appeared on the screen.

It continued even when he wasn’t being shown to the stadium. As Sinner prepared to serve in the first set, one member of the crowd cried out in support of Federer.

“We love you Roger!” they yelled, earning laughs from the rest of the stadium. And Machac had a hilarious comeback.

“What about me?” the Czech star replied, shrugging his arms in the air, getting even more laughter.

Federer approved of the joke, giggling from his plush seat at the baseline. Sinner also cracked a smile before they got back to business.

Sinner later addressed the hilarious moment. ” Yeah, it’s nice. I mean, I always try to stay focused about the game, but, you know, sometimes when this happens it’s also nice,” he said.

“I mean, it was also nice from Machac, you know, to joke around a little bit with the crowd, because that’s, you know, the crowd, they want to see entertainment.

“Obviously Roger is amazing when he watches some matches, or, you know, he shows his love for this sport, and then how much he gave, obviously, for this, yeah, for our tennis. It’s amazing to see him around, and just, you know, to see him or talk to him a little bit, so, yeah, it was a very, very nice moment.”

After leading by a break early in the first set, Machac lost it 6-4 as the top seed pounced in the final game. But the 23-year-old was still in good spirits and continued to crack jokes even as he served to stay in the match in the second set.

At 4-5, Machac lost the first point of the game and rushed to his bench, informing the umpire that he’d broken the frame of his racket. As he switched out his equipment, he called over to Sinner: “Too fast. The rallies is too fast.”

The two-time Grand Slam champion was confused and rushed over to see what the problem was. “The racket is broken. You play too fast,” Machac joked, earning another laugh from Sinner before they resumed play.

The world No. 33 held on but it was the last game he won. Sinner broke again at the end to beat Machac 6-4 7-5, booking his spot in Sunday’s final.