Serena Williams launched her quest for a 24th Grand Slam title with a quickfire demolition of Anastasia Potapova while Naomi Osaka began her Australian Open title defence in emphatic fashion, breaking the net with a serve as she dismantled unseeded Czech Marie Bouzkova on Monday.

However, heavy downpours caused chaos on Monday, forcing organisers to postpone a swathe of matches. While play continued at the three stadiums with retractable roofs, half of the 64 scheduled matches were postponed, ensuring a big backlog for Tuesday.

Wet conditions are unusual for the Australian Open, which is more used to extreme heat and was plagued by smog from bushfires during qualifying, when players suffered coughing fits and breathing problems.

The 22-year-old Japanese, the world’s second highest-paid female athlete after Serena Williams, powered through 6-2, 6-4 in 80 minutes. The 38-year-old American powered past the Russian teenager 6-0, 6-3 in 58 minutes.

World number one and home hope Ashleigh Barty suffered a scare before powering into the second round of the Australian Open on Monday.

The 23-year-old recovered from a slow start to see off Ukraine’s Lesia Tsurenko 5-7, 6-1, 6-1 under the roof at a partisan and wet Melbourne.

Caroline Wozniacki, playing her final tournament, starts with a good win. The 2018 champion beats Kristie Ahn 6-1, 6-3 to reach the second round.

Fifteen-year-old American Coco Gauff beat Venus Williams – the second time the teenager has dumped the veteran out in a Grand Slam first round. Gauff surged into the second round in Melbourne with a 7-6 (7/5), 6-3 victory over the 39-year-old Williams and will play unseeded Romanian Sorana Cirstea next.

Late in the day, former US Open champion Sloane Stephens became the highest seed to exit the women’s draw on day one.

The 2017 Grand Slam winner at Flushing Meadows and 24th seed in Melbourne lost in three sets to Zhang Shuai and is in the midst of a poor run of form.

The Chinese defeated the 26-year-old American 2-6, 7-5, 6-2 with Stephens having now lost all of her three matches in 2020. Stephens similarly lost in three sets to Zhang in the first round in 2018.

Williams threatened to blow away Potapova – who was temperamental at times – in embarrassingly rapid fashion. But the 90th-ranked Russian, overawed in the first set, fought back and broke Williams’ serve in the second, helped by some sloppiness from the American.

Williams double-faulted to go down a surprise 2-1, but there was never a hint of an upset as the American broke back before pulling away to an easy win. She will play Tamara Zidansek next.

Osaka, a two-time Grand Slam champion and one of the prime threats to Williams’s bid to win a record-equalling 24th Major, plays China’s Zheng Saisai in round two.

The third seed, saw her victory march held up for a few minutes early in the second set after a blockbuster serve broke a fitting in the net at the 15,000-capacity Rod Laver Arena.

“It was really tough for me trying to control my nerves,” said Osaka. “It’s tough to play someone you’ve never played before in the first round of a Grand Slam. I hope I’m still standing here at the end of this week.”

Barty, under huge pressure to deliver a home women’s champion for the first time since Chris O’Neil in 1978, plays Polona Hercog of Slovenia or Sweden’s Rebecca Peterson next.

A nation expects, and Barty said after dismissing the 120th-ranked Ukrainian that she had always felt in control, despite the indifferent start.

“It’s all good, it’s amazing to be back out here,” said the Australian, fresh from winning her first title on home soil, in Adelaide, on Saturday. “Really nice to sort it out a little bit at the start of the second set and sharpen up.”

She described the support in the Rod Laver Arena as “absolutely incredible” and said she had been looking forward to playing there. “I couldn’t wait to walk out here... thank you, guys,” she said to cheers.

The first Grand Slam of the year went ahead as scheduled on Monday after air pollution eased in Melbourne. Last week’s build-up to the Australian Open was plagued by choking haze from widespread bushfires, forcing organisers to temporarily delay qualifying matches.

Results

1st round

Zhu Lin (CHN) bt Viktorija Golubic (SUI) 4-6, 6-1, 7-6 (10/5)

Julia Georges (GER) bt Viktoria Kuzmova (SVK) 6-1, 6-2

Petra Martic (CRO x13) bt Christina McHale (USA) 6-3, 6-0

Ekaterina Alexandrova (RUS x25) bt Jil Teichmann (SUI) 6-4, 4-6, 6-2

Barbora Krejcikova (CZE) bt Kaia Kanepi (EST) 7-6 (7/3), 2-6, 6-3

Paula Badosa (ESP) bt Johanna Larsson (SWE) 6-1, 6-0

Petra Kvitova (CZE x7) bt Katerina Siniakova (CZE) 6-1, 6-0

Naomi Osaka (JPN x3) bt Marie Bouzkova (CZE) 6-2, 6-4

Zheng Saisai (CHN) bt Anna Kalinskaya (RUS) 6-3, 6-2

Sorana Cirstea (ROU) bt Barbora Strycova (CZE x32) 6-2, 7-6 (7/5)

Ann Li (USA) bt Lizette Cabrera (AUS) 7-6 (7/4), 7-6 (12/10)

Sofia Kenin (USA x14) bt Martina Trevisan (ITA) 6-2, 6-4

Caroline Wozniacki (DEN) bt Kristie Ahn (USA) 6-1, 6-3

Tamara Zidansek (SLO) bt Han Na-lae (KOR) 6-3, 6-3

Serena Williams (USA x8) bt Anastasia Potapova (RUS) 6-0, 6-3

Ashleigh Barty (AUS x1) bt Lesya Tsurenko (UKR) 5-7, 6-1, 6-1

Coco Gauff (USA) bt Venus Williams (USA) 7-6 (7/5), 6-3

Caty McNally (USA) bt Samantha Stosur (AUS) 6-1, 6-4

Zhang Shuai (CHN) bt Sloane Stephens (USA x24) 2-6, 7-5, 6-2

With AFP Inputs