MELBOURNE: Fourth seed Caroline Wozniacki stormed home on the back of a powerful serve to beat Israel's 29th seed Shahar Peer 6-4, 6-0 and stay alive at the Australian Open on Saturday.

The Dane now faces China's Li Na in the fourth round of the year's opening Grand Slam after seeing off the Israeli in 80 minutes on Rod Laver Arena.

The 19-year-old lost her opening service game to go 2-0 down but from that point on she served superbly to dominate.

Wozniacki had an 81 percent first serve success rate in the opening set and 76 percent overall, the sheer pressure of which told on Peer, who battled bravely in the first set but tired as the match wore on.

"The serve percentage was really high today and I was really pleased about that," she said.

"I felt like I was serving well and winning a lot of my points on it.

"But I think some days you serve well and some days you serve less good. All in all, it was a good performance."

Wozniacki has soared up the world rankings since she reached the final of last year's US Open, where she lost to Kim Clijsters.

But despite being just 19 years old, she showed enormous composure against Peer.

The two players were called on court early after Marcos Baghdatis pulled out of the earlier men's match injured, but Wozniacki said she had kept an eye on the score and when she saw Baghdatis lost the first set 6-0, she decided to start her preparations.

"Actually, I came here and warmed up at 6pm at the stadium," she said.

"Afterwards, I just had a quick look at the scores. I could see it was 6-0 for (Lleyton) Hewitt, so I went to the gym and started working out a little bit just to get the match rhythm, and I got into match mode.

"Afterwards, I heard that he retired, so I was already ready. I went and changed fast, and then we went on court."

She conceded she would have to be at her best against Li, after the Chinese number one came back from a set and a break down to overhaul her in the first round in Sydney last week.

"I'm going to do my best. She's a great player, she beat me last time," she said.

"It's going to be a tough fight.

"She can't be the one dictating the game because then she's dangerous and playing really heavy balls.

"It's just important for me to keep her moving."