The hotly anticipated event is already being billed as "Federer vs. Williams", though they'll be joined by Swiss player Belinda Bencic and American Frances Tiafoe.
It was billed as the battle of the sexes and it lived up to the hype - tennis' two greatest players going rally for rally in the mixed doubles in front of 14,000 fans at RAC Arena last night. "I admire everything she's done on and off the court, we're both fierce competitors and we always want to win".
"This guy (Federer) is great, both off the court and on the court".
The mutual appreciation continued when Williams was asked to assess the abilities of her opposite number, having just faced him on court for the first time.
"It's super exciting", Williams said, looking ahead to her meeting with Federer later in the day.
"It was a great experience, I'm kind of sad it's over - I was just warming up!"
Federer had also looked in fine form as he looks to defend his Australian Open crown, gaining a single break to take the first set against his 20-year-old opponent and then racing through the second.
If we were talking about anyone other than Federer and Williams, it'd be fair to say this is a pretty good way to cap off their careers.
Federer faced three break points in his first service game, but was near flawless from that point on as he wrapped up the contest in 57 minutes at RAC Arena on Sunday night.
Federer eventually clinched it for reigning champion by claiming the winning point in the truncated tiebreak used in mixed doubles with a ideal angled volley.
Williams said it was "like a dream come true".
Tickets were sold out soon after being released for the showpiece encounter, which pits Federer and Williams on court for the first time. "I mean she's equal to me....so from that standpoint, its just really once the movement comes into play that the difference- it becomes bigger", said the Swiss.
"I'll stay on the bike and keep the engine on", Federer said.