The pair, considered perhaps the greatest players in the history of the game, came up against each other for the first time as Switzerland faced the United States at the annual mixed team event held in Perth in Australia.

Going into the mixed doubles tie, which also featured Belinda Bencic for Switzerland and Francis Tiafoe for the US, the overall score read 1-1 at the RAC Arena.

Earlier in the evening 20-time Grand Slam champion Federer defeated Tiafoe 6-4, 6-1 before Williams levelled the tie with a 4-6, 6-4, 6-3 win over Bencic.

The deciding mixed doubles match then ended 4-2, 4-3 to the Swiss.

It means Switzerland top Group B with two wins from two, while the US languish in last place, having now lost twice in consecutive matches. 

Elsewhere, in Australia it was a good day for Great Britain, as Johanna Konta and Andy Murray each won their first-round matches at the Brisbane International.

With both matches taking place in the Pat Rafter Arena, Murray, on his return from a long-term hip injury that kept him out for much of 2018, beat James Duckworth from Australia 6-3, 6-4.

Two matches later Konta, currently ranked 37th on the women’s tour, beat the number three seed and 2017 US Open champion Sloane Stephens in this Women's Tour Association Premier event. 

That match finished 6-4, 6-3.

After his match 31-year-old Murray was visibly emotional.

"I was a bit nervous [before the match], but as the match went on I thought I moved well," the double Olympic gold medallist said afterwards.

"It’s my first match after a big break.

"It’s not easy to sum up [how difficult it has been to return].

"It’s been really hard the last 18 months, been a lot of ups and downs trying to get back on court.

"Being back now I am trying to enjoy it as much as I can, for as long as I can because I am not sure how much longer I have got."

The other stand out result of the day saw the women’s number two seed Naomi Osaka from Japan, last year's US Open champion, beat Australian qualifier Destanee Aiava 6-3, 6-2.