Barty through, Williams out of Open

World number one Ash Barty is through to the fourth round of the Australian Open, defeating world number 29 Elena Rybrankina 6-3, 6-2 at Rod Laver Arena today.

The news wasn't as good for Serena Williams, who will have to wait until the French Open in June for another chance of equalling Margaret Court's Grand Slam record after a shock loss to China's Wang Qiang sent her packing from the tournament.

Barty and Rybrakina both struggled in their early service games, squandering opportunities to gain a decisive advantage as both women had their serve broken in their first two service games.

Barty eventually assumed control as she capitalised on her opponent's unforced errors, claiming the first set 6-3.

Two early breaks of serve in the second had the world number one on her way to a comfortable victory, winning the match in an hour and 20 minutes.

Barty was relieved to progress in to the second week of the tournament.

"I felt I needed to be switched on," Barty said in her courtside interview with Channel Nine.

"A lot of the games were long and tough and [I was] happy to get out of them. The best game I have played this summer so far."

The first big name to exit the tournament is seven time champion Serena Williams, who lost to Wang Qiang of China, 6-4, 6-7, 7-5.

Williams kept the match alive by winning the second set in a tie break, but Wang regained control in the third set, the world number 29 sending Williams packing in the third round for the first time since 2006.

Later today Australia's John Millman will face six time Aus Open winner Roger Federer, while number six seed Stefanos Tsitsipas faces Canadian Milos Raonic at Margaret Court Arena.