Roger Federer's Switzerland beat Serena Williams' USA as the two tennis greats met on court for the first time at the Hopman Cup in Perth, Australia.

Federer and Belinda Bencic beat Williams and Frances Tiafoe 4-2 4-3 (5-3) in a mixed-doubles contest to secure a 2-1 win in the round-robin tie.

Federer and Williams, both 37, earlier won their respective singles matches.

"It was great fun. I really enjoyed playing against Serena. What an honour," said Federer.

"I was nervous returning because people talk about her serve so much. I know why they say it now, she has a wonderful serve.

"She's a great champion, you see how focused she is and I love that about her."

Federer and Williams have won a combined 43 Grand Slam singles titles, and have spent a combined 621 weeks at world number one.

The match had been described as the most anticipated contest involving a male and female player since the 'Battle of the Sexes' in 1973, when 39-time Grand Slam champion Billie Jean King beat former men's world number one Bobby Riggs in straight sets.

"It was a great experience. I'm sad it's over, I was just warming up," said Williams.

"It was so fun to do this at the pinnacle of our careers.

"The guy is great. He's the greatest of all time. There's a reason why he is so great. He has a killer serve. I've watched him all the time but I never realised how good it was. Maybe I could get some tips from him later on."

Before the mixed-doubles contest, Federer beat Tiafoe 6-4 6-1 before Williams levelled the tie with a 4-6 6-4 6-3 victory over Bencic.

The Hopman Cup comprises two singles and a mixed doubles match between nations in a round-robin format with two groups of four. The winners of each group will contest Saturday's final.

Defending champions Switzerland play Greece in their final round-robin match on Thursday while the USA face Great Britain's Cameron Norrie and Katie Boulter.