The quarterfinals are underway at Melbourne Park, as rumours abound about Jannik Sinner's health ahead of his clash with Alex de Minaur. Follow live.

American Danielle Collins is out of the Australian Open following a straight-sets defeat by fellow countrywoman Madison Keys.

Lorenzo Sonego will take on American Ben Shelton in the other men’s quarter-final on Jan 22. Read more at straitstimes.com.

The American rallied from a set down to reach the last four in Melbourne for the third time, and will face No. 2 seed Iga Swiatek next.

As much as any top player, Sinner has been able to expose De Minaur’s lack of first-strike weaponry. The Aussie’s strength is his scrambling and counterpunching, but Sinner serves too well, hits too hard, places the ball too precisely for his defense to be effective. De Minaur hasn’t found a way to hurt, rattle, of disrupt him.

Follow live text and radio commentary as Alex de Minaur plays Alex Michelsen in the Australian Open fourth round.

Iga Swiatek’s latest lopsided win at the Australian Open came via a 6-1, 6-2 score in the quarterfinals against No. 8 seed Emma Navarro on Wednesday. The No. 2-seeded Swiatek not only has not dropped a set so far in the tournament,

Alex de Minaur is through to the quarterfinals of the Australian Open for the first time, defeating American giant-killer Alex Michelsen.

An embarrassing on-air gaffe in a post-match interview with Madison Keys has added to Channel Nine’s horror run at the Open this year.

Ahead of Friday’s men’s semi-finals, there are concerns over Novak Djokovic’s fitness, after the 10-time champion missed practice on Thursday. The Serb is due to play Alexander Zverev, while world No 1 Jannik Sinner prepares to face Ben Shelton.

Australian Open has been intense, with the men's and women's singles tournaments heating up. Here's what to know about the current bracket.