Watch Video: Serena Williams feels the Bieber fever at 2016 Australian Open

WTA world No. 1 Serena Williams caught some “Bieber fever” ahead of the 2016 Australian Open at Melbourne Park.

Just few days before the start of the 2016 Australian Open, Williams posted on Instagram a video of herself lip-syncing one of Justin Bieber’s new hit singles, suggesting that the women’s defending champion is setting in lightly at the first Grand Slam event of the year.

The 21-Grand Slam winner withdrew from the Hopman Cup exhibition tournament because of a sore knee, clouding chances of retaining her Australian Open title against top-talented players around the world.

But despite an early setback ahead of her title defense, Williams is convinced she is still on track for a second straight Australian Open title. Williams said she is feeling great and her knee is “doing much better” despite the fact that her bone-on-bone condition in her knees is career-threatening.

“My body is feeling great now,” Williams said, reports Fox Sports. “Obviously I had a hiccup but right now it is doing much better. I’ve had a few days of training so it’s looking good.”

Williams will open her Australian Open campaign against Italy’s Camila Giorgi and will be joining Maria Sharapova in the same group bracket. Williams defeated Sharapova last year to claim his sixth Australian Open title, but the former could face the “Siberian Siren” as early as the semifinal round, according to Sports Illustrated.

Meanwhile, injuries or illness have plagued most of the women’s top 10 in recent weeks, putting more pressure on the WTA organisers to reform the players’ playing schedule. Only Williams’ sister Venus and Flavia Pennetta are among those unscathed by injuries.

Other competitors like Simon Halep, Garbine Muguruza, Agnieszka Radwanska and Sharapova have all pulled out of build-up tournaments because of injury concerns, while Petra Kvitova and Angelique Kerber got hit by gastroenteritis, and Lucie Safarova skipping Melbourne because of a bacterial infection.

“Clearly one of the big issues that we have right now is dealing with... getting our athletes through the season healthy,” WTA CEO Steve Simon said, reports The National.

Visit the event’s official website for the complete list of the 2016 Australian Open draw.