Zheng Qinwen recovered from a "stupid mistake" to begin her Australian Open bid with a straight-set win on a rain-disrupted first day in Melbourne.

Chinese fifth seed Zheng, beaten by Aryna Sabalenka in last year's final, won 7-6 (7-3) 6-1 against Romanian qualifier Anca Todoni under the roof on Rod Laver Arena.

The Olympic gold medallist served for the opening set at 5-4 40-0, but could not take any of her three set points.

Todoni, 20, had never beaten a top-50 opponent and had the chance to move halfway to a shock win after creating three set points on Zheng's serve at 6-5.

But she could not convert and Zheng, 22, held before stepping up a gear in the tie-break.

The second set was more straightforward as Zheng, backed as usual by a huge number of Chinese fans, broke early before cruising through to victory.

"The first set is always not easy, especially because I was doing stupid mistakes - I don't know what happened there," she said.

"But I am happy to get through."

On expectations rising after winning the Olympic title, she added: "Of course there starts to be more pressure but [the fans] are pushing me to become a better person and better athlete.

"I like to play with pressure. Like what Billie Jean King says - pressure is a privilege. I love this sentence.

"Let's keep going and playing with pressure."

While Zheng was able to complete her match indoors, a heavy thunderstorm caused play on the outdoor courts to be suspended until 17:00 local time (06:00 GMT).