The Australian Open finally got under way at Melbourne Park on Monday, three weeks later than originally scheduled because of the coronavirus pandemic.
Japan's Naomi Osaka, the third seed, struck the first serve of the tournament on Rod Laver Arena against Russia's Anastasia Pavlyuchenkova in the women's singles
Serena Williams follows her on court with men's world number one Novak Djokovic playing in the night session.
Veteran American Venus Williams kicked off proceedings on the neighbouring main show court, Margaret Court Arena, against Kirsten Flipkens of Belgium in front of a sprinkling of fans, with crowd numbers limited to 30,000 a day.
The tournament is known as the "Happy Slam" for its convivial atmosphere but the pandemic has cast dark clouds over this year's build-up.
Djokovic is going for a record-extending ninth Melbourne Park crown, Serena Williams is still chasing the major she needs to match Margaret Court's all-time mark of 24 Grand Slams and Osaka is after her second Australian Open title in three years on the back of her US Open win last year.
But while those are familiar themes, the first Grand Slam of the year has a different vibe, played in front of fewer spectators with mandatory mask-wearing and sanitising stations prominent in a zoned-off Melbourne Park with spectators unable to move freely around the grounds.
Australia has largely contained the virus, but officials are desperate to avoid further problems from Covid-19.
Preparations had to be hastily rearranged as late as last Wednesday when a coronavirus case at a tournament hotel -- the city's first local infection in 28 days -- forced a suspension of play.
Hundreds of players and officials were tested and all were negative.
Serena Williams, the 10th seed, begins her campaign against Laura Siegemund of Germany, four years after the American great's last Grand Slam victory, when she was pregnant.
Djokovic begins against world number 66 Jeremy Chardy, having never lost to the Frenchman in 13 previous meetings.
US Open winner Dominic Thiem, runner-up in Australia last year to Djokovic, Germany rising star Alexander Zverev and former champion Stan Wawrinka are all in action on the first day.
So is women's world number two Simona Halep, who has been battling a back injury which hampered her preparations. She will open the evening session on Rod Laver against Australian wild card Lizette Cabrera.
Combustible Australian Nick Kyrgios begins his campaign on his favourite John Cain Arena, where he has raucous support, against Portugal's Frederico Ferreira Silva.
Kyrgios last week smashed a racquet and threw it out of the stadium during a warm-up defeat.
Before that he had labelled Djokovic a "tool" for demanding better conditions for players during quarantine.
Top women's seed Ashleigh Barty, defending champion Sofia Kenin and 20-time men's singles Grand Slam champion Rafael Nadal all to begin their challenge for this year's Australian Open on Tuesday's second day.