Defending champion Aryna Sabalenka extended her Australian Open winning streak to 15 matches on a rain-soaked opening day at Melbourne Park.
Less than an hour of play was possible on the outside courts before a huge thunderstorm hit Melbourne Park, sending spectators running for cover and causing a delay of more than six hours.
The matches continued as scheduled on the three covered courts, and Sabalenka opened the night session on Rod Laver Arena with a 6-3 6-2 victory over former US Open champion Sloane Stephens.
While it was a tough draw on paper, Stephens has slipped to 81 in the rankings and, barring a mini revival from the American when she won three games in a row after losing the first four, this was smooth sailing for Sabalenka.
Fifth seed Zheng Qinwen also safely reached round two. The Chinese star, the runner-up last year in the women's singles who went on to win Olympic gold in Paris, did not have things all her own way against Romanian qualifier Anca Todoni but battled to a 7-6 (7-3) 6-1 victory.
Zheng looked in complete control serving for the set at 5-4 and leading 40-0 only for Todoni to win five points in a row.
The Romanian then held three set points with Zheng serving at 5-6 but could not take any of them and things were comfortable for the fifth seed thereafter.
"The first match is always not easy," said Zheng in her on-court interview. "She's playing really good but I was doing a bit stupid mistakes at 5-4 40-0, I don't know what happened there."
Teenager Mirra Andreeva could be a factor come the latter stages of the tournament and she began strongly with a 6-3 6-3 victory over Marie Bouzkova.
Sonay Kartal's comeback fell short as her Australian Open debut ended in defeat to Spain's Jessica Bouzas Maneiro.
British number three Kartal rose rapidly up the rankings during the second half of last season, winning a first WTA Tour title in Tunisia and breaking into the top 100.
That earned her a place in the main draw in Melbourne, and she was the only British player in action on a rain-soaked opening day, with the contest finally getting under way three and a half hours after its scheduled slot.
Kartal was blown away in the opening set but recovered from 3-0 down in the second set to force a tie-break before losing out 6-1 7-6 (7-5).
