Azarenka the latest star to withdraw from Australian Open

Victoria Azarenka's absence was confirmed as she joined reigning champion and 23-time major winner Serena Williams on the sidelines.

A two-time Australian Open winner, Victoria Azarenka's participation had been in doubt.

The Australian Open has been dealt another blow after two-time champion Victoria Azarenka withdrew a week out from the year's opening grand slam.

Azarenka's absence was confirmed on Monday as she joined reigning champion and 23-time major winner Serena Williams on the sidelines, while five-time runner-up Andy Murray and Kei Nishikori have already withdrawn on the men's side.

Read: 'I feel ready!', Djokovic graces Rod Laver in Australian Open boost

The 28-year-old former world number one – who pulled out of the Auckland Open – was granted a wildcard for the Australian Open last month but she will not make the trip to Melbourne amid an ongoing custody battle over her son.

Azarenka has not featured on the WTA Tour since Wimbledon in July, sitting out the US Open and the Fed Cup final due to the childcare issue.

"It's unfortunate that Azarenka is unable to travel to Australia this year," tournament director Craig Tiley said.

"The Australian Open is her favourite tournament and she's looking forward to returning to Melbourne next year."

Belarusian Azarenka – winner of the Australian Open in 2012 and 2013 – only made six appearances in 2017, claiming four victories.