Halep finally registered a victory over Serena in 2014, winning their WTA Finals group match 6-0, 6-2 (Getty)

Rivalry record: Serena Williams vs Simona Halep

Ashleigh Barty carried home hopes into the quarterfinals with a 4-6, 6-1, 6-4 win over Maria Sharapova (Getty)

Picture perfect: Best images from the fourth round of the 2019 Australian Open

Seven-time Australian Open champion Serena Williams was in commanding form as she dropped only three games in her third-round match. (Getty)

Serena, Simona succeed: The best pictures from the 2019 Australian Open third round

Simona Halep was forced into another lengthy match but battle back to beat Sofia Kenin, 6-3, 6-7(5), 6-4. (Getty)

Halep and Serena win through: Second-round snapshots from the 2019 Australian Open

Doha 2008 was the scene of the first meeting between Maria Sharapova and Caroline Wozniacki, with the former winning, 6-0, 6-1. (Getty)

Rivalry record: Maria Sharapova vs Caroline Wozniacki

Top seed Simona Halep was made to work before beating Kaia Kanepi in three sets (Getty)

Melbourne moments: Best images from Round 1 of the 2019 Australian Open

On three occasions she has won the US Open and Australian Open back-to-back, most recently in 2015. Only Stefanie Graf can match that achievement. (Getty)

Major achievement: Serena Williams' incredible Slam stats

No. 26 Dominika Cibulkova reached the final in 2014 but could not overcome Li Na (Getty)

Australian Open 2019: 32 seeds and their best Melbourne result

Serena Williams, Hopman Cup 2019 (Getty)

24 and more: Potential storylines and milestones in 2019

Victoria Azarenka made good on her top billing six years ago, seeing off Li Na 4-6, 6-4, 6-3 in the final (Getty)

Leading the way: How top seeds fared at Australian Open over last decade

Caroline Wozniacki won her first Grand Slam event in 2018, beating Simona Halep 7-6, 3-6, 6-4 (Getty)

Magic in Melbourne: A decade of Australian Open champions

Before play began, this group of WTA stars participated in All-Access Hour on board cruising yacht in the Sydney Harbor.

From paradise to pavlovas: WTA stars see Sydney sights