Gallery: The best pictures from an action-packed day four at the Australian Open

Australian Open camera

Third-round action continued at the Australian Open with Novak Djokovic, Alexander Zverev, Serena Williams and Simona Halep all in action at Melbourne Park.

Enter Kei Nishikori.
Kei Nishikori arrives on court

Go on, guess who it is.
Kei Nishikori takes a break

The above picture was Nishikori as well, but onto a pumped up Elina Svitolina.
Elina Svitolina celebrates

Blowing kisses after her win over Viktoria Kuzmova.

Elina Svitolina blowing kisses

World number one Simona Halep had to dig deep to come through her second round match. Very deep.

Simona Halep determined

From behind the lens.
Australian Open camera

A Stan Wawrinka backhand.
Stan Wawrinka backhand

And then it rained and the ball kids had to do some mopping up.
Australian Open rain ball kids mopping up

Serena Williams was in action, and she was certainly enjoying herself.

Serena Williams curtsies

Alexander Zverev looked nervy from the off, though, even with himself cheering him onto court.

Alexander Zverev entrance

The face of a man who’s had to deal with Novak Djokovic’s brilliant defence for two hours…

Jo-Wilfried Tsonga frustrated

Certainly, the world number one seemed to be managing to reach pretty much everything!

Novak Djokovic reaches

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