Serena Williams returns to the spotlight at the US Open on Wednesday bidding to extend her long goodbye to tennis in a second round clash with world number two Anett Kontaveit.

The 23-time Grand Slam-winning sporting and cultural icon, playing in what is expected to be her final tournament, faces Kontaveit in another prime-time match at the Arthur Ashe Stadium.

On Monday, a galaxy of stars and celebrities turned out to watch Williams make her 2022 tournament bow with a straight sets first round win over Montenegro's Danka Kovinic, the world number 80.

Williams has signalled that this year's US Open will be her last tournament as a professional, revealing in a Vogue magazine essay this month that the "countdown" to retirement had begun.

But the 40-year-old demurred when invited to confirm definitively that she would be retiring after her US Open campaign.

"I have been pretty vague about it, right? I'm going to stay vague because you never know," Williams said with a smile.

She also admitted that the intoxicating atmosphere surrounding Monday's first round match -- which felt more like a rock concert than a sporting contest -- would be hard to walk away from.

"It's extremely difficult still because I absolutely love being out there," she said.

"The more tournaments I play, I feel like the more I can belong out there. That's a tough feeling to have, and to leave knowing the more you do it, the more you can shine.

"But it's time for me, you know, to evolve to the next thing."

Whether Williams is able to extend her US Open campaign further than Wednesday's second round assignment remains to be seen.

If she is able to rediscover more consistency in her serve, she may well have enough firepower to take down Kontaveit, whose world number two ranking belies a modest record in Grand Slams.

Her best result in a major championship is a single quarter-final appearance at the 2020 Australian Open.

- Medvedev, Murray in action -

Day three of the Open sees the men's draw in full swing with defending champion and top seed Daniil Medvedev following Williams on Arthur Ashe with a second round tie against unheralded Frenchman Arthur Rinderknech.

A victory for Medvedev could potentially set up a David v Goliath third round meeting with Chinese qualifier Wu Yibing.

Wu became the first Chinese man in 63 years to win a singles match at a Grand Slam when he knocked 31st seed Nikoloz Basilashvili out of the tournament.

The 22-year-old, ranked 174th in the world, is aiming to extend his campaign on Wednesday with a second round clash against Portugal's Nuno Borges. The winner will face either Medvedev or Rinderknech.

In other men's action, 2012 champion Andy Murray hopes to haul his injury prone 35-year-old body through another contest staged in the midday heat and humidity.

Murray faces Emilio Nava of the United States on the Arthur Ashe court. On Monday, Murray admitted the conditions had been tough during his straight sets defeat of Argentina's 24th seed Francisco Cerundolo.

"It felt like five sets," Murray said after the win.