Ana Ivanovic wasn't at her best at the Australian Open on Tuesday but still had too much for her first-round opponent.

The popular fourth seed produced 28 unforced errors against Sorana Mihaela Cirstea of Romania, but still posted a 7-5 6-3 victory.

Despite losing her serve three times, the Serbian took a scrappy first set after 56 minutes.

Ivanovic became frustrated in the second set as the computerised line-calling system Hawk-eye broke down on the Vodafone Arena.

She blew some early chances to seal victory, but finally booked her place in the last 64 where she will meet Tathiana Garbin.

Although she was not entirely satisfied with her first-round effort, Ivanovic is happy with her build-up to the season-opening grand slam.

"I had really good preparation in the off-season and I feel very fit,'' she said.

"Last week I played some good tennis. But I think I can perform better."

Meanwhile, ninth seed Daniela Hantuchova made light work of Vania King as she swept to a 6-3 7-5 victory.

Anna Chakvetadze, seeded six, had an even easier time and did not have to hit a ball in anger to progress. Her opponent, Andrea Petkovic, withdrew with an injury suffered in the warm-up.