Two-time Grand Slam champion Simona Halep avoided becoming the latest big casualty at the Australian Open when she beat Kazakhstan's Yulia Putintseva to reach the last 16 on Saturday.

The fourth seed won 6-1, 6-4 and plays Belgian 16th seed Elise Mertens or world number 600 CiCi Bellis of the United States next in Melbourne.

Serena Williams and reigning champion Naomi Osaka both lost on Friday and second seed Karolina Pliskova followed them out the exit door on Saturday.

But the 28-year-old Halep, last year's winner at Wimbledon, said: "I am not focusing on other players, just on myself. At this level, every match is really tough."

Halep, who also won the French Open in 2018, said being the current Wimbledon champion meant nothing in terms of trying to win the Australian Open for the first time.

"It's been a great year last year but this is different tennis," she told Rod Laver Arena. "I am ready, I give everything I have to win and really, really happy to be in the second week now."