San Francisco Frontiers - Serena back in spotlight, Murray marches on

The 23-time Grand Slam-winner, playing in what is expected to be her final tournament, headlines the night session 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.

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

If she rediscovers 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.

- Sakkari upset -

In early women's draw action on Wednesday, China's Wang Xiyu produced a memorable upset after dumping out third seed Maria Sakkari of Greece, winning 3-6, 7-5, 7-5.

The 21-year-old had never been past the second round of a Grand Slam tournament before, but uncorked 35 winners while saving 12 of 17 break points to secure her win.

Wang, ranked 75th in the world, has happy memories of New York, having won the junior US Open title at the venue in 2018.

"I'm just trying my best to save every ball," Wang said in her on-court interview. "I'm trying and learning."

Elsewhere Wednesday, Tunisia's beaten Wimbledon finalist Ons Jabeur sailed into the last 32 with a 7-5, 6-2 win over Elizabeth Mandlik of the United States.

Fifth-seeded Jabeur became the first Arab or African woman in history to reach a Grand Slam final at Wimbledon in July, where she was beaten by Kazakhstan's Elena Rybakina.

The USA's 12th-seeded Coco Gauff, meanwhile, advanced to the third round with a 6-2, 7-6 (7/4) win over unseeded Romanian Elena Gabriela Ruse.

That win sets up an all-American showdown between Gauff and 20th seed Madison Keys, who needed three sets to edge past Italy's Camila Giorgi, winning 6-4, 5-7, 7-6 (10/6).

- Murray advances -

In the men's draw, defending champion and top seed Daniil Medvedev will follow 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 on Monday.

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 matches, 2012 champion Andy Murray advanced to the third round for the first time in six years with a four-set win over American wildcard Emilio Nava.

The 35-year-old Scot prevailed 5-7, 6-3, 6-1, 6-0 and is delighted at how his injury-prone body is holding up thus far.

"Physically this is the best I've felt in the last few years," said Murray.

"My movement is by far the best it's been in a long time. I'm getting closer to where I want to be and hopefully I can have a deep run here."

Murray will face world number 14 Matteo Berrettini in the next round. The Italian defeated France's Hugo Grenier 2-6, 6-1, 7-6 (7/4), 7-6 (9/7).

K.Gray--SFF