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.