PERTH: Tennis royalty Roger Federer and Serena Williams have been pounding balls across the net for more than 20 years and they are back for yet another season, starting in Perth at the mixed teams Hopman Cup from Saturday.
Both 37 years old and with 43 Grand Slam singles titles between them, Federer is now a father and Williams a mother but tennis keeps calling, with neither showing any sign of quitting.
Flying Federer leads Switzerland in defence of the Hopman Cup title he won alongside Belinda Bencic earlier this year, with the pair teaming up once again.
Williams returns to the country for the first time since her famous Australian Open win in 2017, when eight-weeks pregnant with baby Alexis Olympia.
She partners rising American star Frances Tiafoe in her fifth visit to Western Australia.
In a mouthwatering prospect, Switzerland play the United States on January 1 with two of the greatest players ever facing each other in the mixed doubles.
Federer conceded it was a once-in-a-lifetime match-up and one he was looking forward to.
"We'll probably play it down a little bit and say it's not that big of a deal for us, it's just another tennis match, but it really isn't because it's probably going to happen once and never again," he said on Thursday.
The Swiss great has spent the off-season training hard ahead of the defence of his Australian Open title and said he was happy with his fitness.
"The last three or four weeks have been very intense. I'm very excited and motivated for this next season."
The last two seasons the Swiss legend started in Perth, he went on to win the opening Grand Slam of the year.
Williams played an exhibition against sister Venus in Abu Dhabi this week, but Perth will be her first competitive event since her meltdown in the US Open final this year.
She received a code violation for coaching, a penalty point for racquet abuse and a game penalty for calling the umpire a "liar" and a "thief" during her defeat by Naomi Osaka.
Federer later said Williams "went too far" and should have walked away, adding an edge to their upcoming encounter.
Williams opted not to talk about the rant in Abu Dhabi, instead preferring to look forward.
"My fitness, I feel like I'm pretty fit," she said, adding that she was excited by another season as she primes to win an eighth crown at Melbourne Park to match the record 24 Grand Slam titles held by Margaret Court.