PARIS, July 28 — Simone Biles will make her eagerly anticipated first appearance at the Paris Olympics on Sunday while British breaststroke king Adam Peaty aims to emulate Michael Phelps in the swimming pool.

The United States will launch their bid for a fifth successive men's basketball title against Serbia, who can call upon three-time NBA MVP Nikola Jokic.

But there are serious questions over Rafael Nadal's participation in the tennis singles at Roland Garros after he teamed up with Carlos Alcaraz to win their men's doubles opener.

Nadal is still listed to face Hungary's Marton Fucsovics on Sunday, with Novak Djokovic lying in wait, but the 14-time French Open champion, who has a thigh injury, said: "I don't know if I am going to play tomorrow or not."

After rain marred Friday's opening ceremony and the first full day of action on Saturday, organisers will be heartened by a forecast of sunny and dry weather for day two.Gold medals will be up for grabs in shooting, mountain biking, skateboarding, archery, canoeing, fencing and swimming.

But it is the American gymnast Biles who will be the focus of much of the attention in the French capital as she begins her bid to burnish her Olympic legacy.

Biles, who won four golds at the 2016 Rio Olympics, withdrew from multiple events at the Tokyo Games as she battled the disorientating condition that gymnasts call "twisties".

She still went home with a silver and bronze and won plaudits by talking openly about mental health struggles.

After taking two years out, Biles made a triumphant comeback at the US Classics last year. That was followed up by four world titles to take her tally to an astonishing 23.

The United States team are eager to take the pressure off Biles, 27.

Women's team technical leader Chellsie Memmel said Biles must not feel they are "relying" on her.

"I don't say, 'You are keeping us all together, we're relying on you and you alone'," Memmel said on the eve of the Games.

Peaty v Qin

The swimming competition started in electric style on Saturday with Australia's Ariarne Titmus defending her women's 400m freestyle crown.

Three golds are going begging on Sunday: men's 400m individual medley, women's 100m butterfly and men's 100m breaststroke.

The 100m breaststroke has all the makings of a thriller, pitting defending champion Peaty against China's world champion Qin Haiyang.

World record-holder Peaty is trying to match Michael Phelps and win a third straight gold medal in the same event.

The 29-year-old Peaty, who has struggled with depression, said after Saturday's heats that he was feeling calm.

"If anything too relaxed in the sense of, it doesn't feel like we're here at the moment," he said.

Qin, the 200m world record-holder, was reportedly among the 23 Chinese swimmers who tested positive for a banned drug in late 2020 to early 2021.

He and Chinese swimming chiefs have denied wrongdoing, saying they tested positive after inadvertently consuming tainted food during domestic competition.

La Defense Arena will crank up the noise for the men's 400m individual medley, where France's great swimming hope Leon Marchand – nicknamed "the shrimp" – will be favourite for gold.

Beach volleyball will come under the spotlight when convicted rapist Steven van de Velde plays for the Netherlands.

He was convicted in 2016 of raping an underage girl and sentenced to four years in prison.

The Netherlands' decision to pick the 29-year-old sparked outrage in the lead-up to the Games and he is not staying at the athletes' village. — AFP