British number one Andy Murray says he will be "ready" for big-serving Australian Sam Groth as he bids to progress to the third round of the Australian Open.
Groth, 28, who has the fastest serve in world tennis, faces Murray in the early hours of Thursday morning.
"I'll need to return well and pass well if I want to win," Murray said.
Compatriot Johanna Konta, the world number 47, beat China's Zheng Saisai 6-2 6-3 in round two.
The British number one, 24, is making her Australian Open debut and knocked out eighth seed Venus Williams in the opening round.