If Roger Federer says it’s a big deal, it is a big deal.

Two of the greatest players in tennis history will face off in probably the most anticipated Hopman Cup tie in the event’s history on Tuesday night.

Serena Williams is currently in Abu Dhabi for an exhibition match against her sister Venus but is due to arrive in Perth tomorrow ahead of the USA’s opening tie against Greece on Monday.

But it’s the clash between defending champions Switzerland and the Americans a night later that has fans salivating. Williams and Federer, who boast 43 grand slam singles titles between them, have never met on court and are set for a mixed-doubles encounter.

Tournament director Paul Kilderry confirmed the session had sold out soon after they released the tickets.

“We stopped selling tickets after a few days so we might release a few more but it basically sold out straight away,” he said.

“Two of arguably the biggest stars on the planet in any sport playing against each other is going to be amazing and the interest level is going to be all around global tennis.

“Everyone is going to have a peek and see what happens, so it’s really exciting and it’s going to be huge.”

Federer arrived in the early hours of yesterday morning and has an open practice session at RAC Arena tonight.

He admitted his showdown with Williams had been on his mind.

“Thankfully I’m not playing her in singles,” Federer said.

“I’m very excited to be playing against her and watching her up close. I’ve seen her on the telly.

“In the stadium watching her like this when she plays Belinda (Bencic) will be a nice treat. For me to be playing against her in the doubles, that’s definitely something very special.

“She is a champion and a winner ... so I’m sure she also wants to do well.

“I agree, it’s a big deal. We’ll probably play it down a little bit, say it’s not that big a deal for us, it’s just another tennis match.

“But it really isn’t because it’s probably going to happen once and then never again and that’s why I hope we’re both going to be injury-free when that day comes around. We’re just going to try our very best.”

The match-up comes with the future of the event in doubt ahead of the introduction of the ATP Cup in 2020, but Federer said he hoped to return to Perth for top-level competition.

“Great tennis will come here in the future,” he said. “You have a wonderful arena with great tennis and great history here, too. I’m sure it’s going to continue in some shape or form.”