Serena Williams underlined why she is the Australian Open favourite with a rapid first-round win, while defending champion Naomi Osaka also advanced.

Williams, chasing a record-equalling 24th Grand Slam title, took the first set in 19 minutes in a 6-0 6-3 victory over Russia's Anastasia Potapova.

Third seed Osaka started slowly against Marie Bouzkova before winning 6-2 6-4.

World number one Ashleigh Barty and Britain's Johanna Konta are also in action on Monday.

Osaka, who broke the net with one of her serves against Czech Bouzkova, will play China's Saisai Zheng in the second round in Melbourne.

Williams, who won her first WTA title in three years in the run-up to the opening Grand Slam of the year, will play Slovenia's Tamara Zidansek next.

The 38-year-old American was made to work harder in the second set by 18-year-old Potapova, who broke in the third game of the second set after a double-fault by Williams.

But Williams immediately broke back and completed a convincing victory with 58 minutes on the clock.

There was an even faster win for seventh seed Petra Kvitova, with the 2019 runner-up demolishing fellow Czech Katerina Siniakova 6-1 6-0 in 51 minutes.

'I didn't do anything to you' - Osaka on social media exchange

While Osaka was happy to get through to the next round, she was less impressed with one comment she had read on social media - and decided to reply.

One user had posted "Boooooooo - Don't want her to win - Hate her interviews - Not Cute - Annoying" on the event's official Twitter page, with the Japanese later replying: "Are you big mad or little mad?" before telling reporters she could not understand why someone would jeer her like that.

"She was hating. What would her children think? You're just going to come on the Internet and boo me for no reason? I didn't do anything to you," Osaka said.

"She was very upset. I also wonder, people like this, if they see you in person, I wonder what they would do?"

Wozniacki through but Strycova out

Former champion Caroline Wozniacki got her final tournament before retirement off to a good start with a 6-1 6-3 victory over American Kristie Ahn.

Other winners on day one were Croatian 13th seed Petra Martic, who beat American Christina McHale 6-3 6-0 to set up an encounter with 2018 Wimbledon semi-finalist Julia Goerges of Germany, and 14th seed Sofia Kenin.

But last year's Wimbledon semi-finalist Barbora Strycova was beaten 6-2 7-6 (7-5) by Romania's Sorana Cirstea.

The tournament started as scheduled on Monday after air quality improved in Melbourne, although some matches were later interrupted by rain.

Last week's qualifying event had been disrupted by delays because of the air pollution caused by widespread bushfires.