NEW YORK -- Six-time winner Serena Williams got off to a winning start Tuesday at a US Open like no other, being played without spectators and with stringent measures to prevent Covid-19 infections.
Williams powered past 96th-ranked Kristie Ahn 7-5, 6-3 as she launched her protracted pursuit of a record-equaling 24th singles Grand Slam title on day two at Flushing Meadows.
Elsewhere, Andy Murray fought back from two sets down to win a five-set thriller against Japan's Yoshihito Nishioka, in his first singles Grand Slam match in 18 months because of injury and the coronavirus pandemic.
Williams overcame the loss of her first service game in the opening set to advance at a virtually empty Arthur Ashe Stadium, where artwork by black artists is displayed in honor of the Black Lives Matter movement against racial injustice.
"I was really happy with how I just fought for every point no matter how I was playing," said Williams, joking that it felt like she hadn't won a match in straight sets "since the '90s."
It has been more than three years since Williams won her 23rd Grand Slam title at the 2017 Australian Open -- when she was already pregnant with daughter Olympia.
She has come close since, reaching four major finals only to come away empty-handed.
Williams needs one more to equal Margaret Court's record and her chances should be improved by the absence of several top players because of coronavirus concerns or injury.
World number one Ashleigh Barty, the second-ranked Simona Halep and Canadian Bianca Andreescu -- who stunned Williams in last year's final -- are all absent from the behind-closed-doors tournament.
A title win for Williams would also see her become the most decorated women's player at the US Open in the modern era.
She is currently tied with Chris Evert for most US Open women's titles with six.
- Navarro tribute -
Earlier, Murray secured a stunning 4-6, 4-6, 7-6 (7/5), 7-6 (7/4), 6-4 come-from-behind victory in a bruising 4 hr and 39 min encounter against the 49th-ranked Nishioka.
The Scotsman, who who has barely played in 2020, said he had learnt a lot about his physical condition and the metal hip he received during surgery last year.
"I've just played a four-and-a-half hour match when I never thought I'd be able to," he told reporters.
"I'm not sitting here with my hip throbbing and aching. I'll be able to sleep fine tonight and things like that."
Murray will play 15th seed Canadian Felix Auger-Allassime in the second round.
In early matches, 10th seed Garbine Muguruza, the 2016 French Open champion and 2017 Wimbledon winner, advanced to round two with a 6-4, 6-4 victory over Japan's Nao Havino.
She dedicated the win to compatriot Carla Suarez Navarro, who revealed Tuesday that she had been diagnosed with Hodgkin lymphoma and will require six months of chemotherapy.
"You know, she's such a nice woman, so sweet, so kind, so humble. When these things happen to these good people, I feel, like, so sad about it," said Muguruza.
Also in the women's draw, ninth seed Johanna Konta beat compatriot Heather Watson 7-6 (9/7), 6-1 in a tie dubbed the "Battle of Britain."
And 16th seed Elise Mertens of Belgium cruised into the second round with a 6-2, 6-2 win over Germany's Laura Siegemund.
- Thiem advances -
US hope Amanda Anisimova, seeded 22nd, also made sure of her place in the second round with a hard-fought win over Bulgaria's Viktoriya Tomova.
And American Sofia Kenin needed just over an hour to score a 6-2, 6-2 win over unseeded Belgian Yanina Wickmayer at Louis Armstrong Stadium.
In the men's competition, number two seed Dominic Thiem progressed to round two when opponent Jaume Munar retired after the second set at Louis Armstrong Stadium.
Munar abandoned before the start of the third set, with Austria's Thiem leading 7-6 (8/6), 6-3.
Thiem and third seed Daniil Medvedev are high up in the draw due to the absence of Rafael Nadal, over coronavirus fears, and Swiss legend Roger Federer, due to injury.
Thiem now faces India's Sumit Nagal, who became the first Indian man since 2013 to the reach the second round of a Grand Slam event with a 6-1, 6-3, 3-6, 6-1 win over Bradley Klahn of the United States.
The US Open is taking place in a spectator-free bubble at the US National Tennis Center in New York.
Players movements are tightly controlled and everyone onsite is being tested regularly to minimize the risk of infection.
France's Benoit Paire was withdrawn on the eve of the tournament Sunday after returning a positive test.
© Agence France-Presse