Federer pokes fun at age with hilarious dad joke

Roger Federer has poked fun at his advancing years with a comical joke at the Hopman Cup New Year's Eve ball.

The Swiss superstar is in Perth to team up with the 20-year-old Belinda Bencic at the mixed-teams exhibition event ahead of the Australian Open.

With their work on the court coming naturally, it was at the ball where the players had to step up their game as they were tasked with introducing their teammates.

"I'd like to introduce my partner," Federer began, before he turned a misstep into a call that had Bencic and everyone in the crowd crying tears of laughter.

"She's so young... or I'm so old I could be her dad!"

The 36-year-old, who has four young children of his own with wife Mirka, had not even shared Bencic's name before he'd cracked himself up.

After managing to stop herself from laughing too hard, Bencic hit back with a spin on the old needs-no-introduction line.

"And I'd like to introduce the ultimate quokka selfie king," she said.

"And grand slam champion and all of that, Roger Federer!"

Federer, of course, met some quokkas on Rottnest Island on his first day in Australia.

The Swiss duo weren't alone in making some hilarious calls at the New Year's Eve ball.

Daria Gavrilova is dating fellow Australian tennis player Luke Saville, so it's a wonder how she knows this odd fact about Thanasi Kokkinakis.

"He has the best pick-up lines," Dasha said.

Others in attendance were Canada's Genie Bouchard and Vasek Pospisil, the United States' Jack Sock and Coco Vandeweghe and Germany's Angelique Kerber and Alexander Zverev.

Federer and Bencic defeated Japanese duo Yuichi Sugita and Naomi Osaka in their first rubber of the Hopman Cup, though Osaka got the better of Federer with this incredible exchange in the mixed doubles: