Sha'Carri Richardson goes for Olympic glory in the women's 100m on Saturday and Simone Biles chases a third gold in Paris, as an Algerian boxer at the centre of a gender row returns to action.

On the penultimate night of swimming, Katie Ledecky, now the most decorated US woman Olympian, seeks to add 800m freestyle gold to her 1500m title.

And on the clay courts of Roland Garros, Zheng Qinwen takes on Donna Vekic with a chance to win China's first tennis singles gold.

Flamboyant US track star Richardson is the reigning world champion over 100m and the fastest woman in the world this year with a brisk 10.71sec under her belt.

The 24-year-old Texan, aiming to become the first American since Gail Devers in 1996 to win Olympic 100m gold, sailed through Friday's heat in 10.94sec.

Richardson is competing in Paris three years after her Olympic dreams in Tokyo were wrecked by a positive test for marijuana following her victory at the US trials.

Saint Lucia's Julien Alfred is Richardson's main rival but the fastest time in the heats belonged to Marie-Josee Ta Lou-Smith, who won her heat in 10.87sec ahead of Jamaica's Shelly-Ann Fraser-Pryce, a two-time 100m gold medallist.

The semi-finals and final of the 100m both take place on Saturday evening.

“To be an athlete here, competing with the energy, with a great appreciation for the track and field, it gives great support to be a track and field athlete,” said Richardson.

“So I'm super-excited to compete on the Olympic stage.”

The second full day of athletics in Paris also includes the women's triple jump, the men's shot put and the conclusion of the men's decathlon.

Golden Biles

After her harrowing Olympic experience in Tokyo, where she withdrew from multiple events because of the mental block gymnasts call the "twisties", Biles already has two golds under her belt in the French capital.

The 27-year-old, who has won team gold and the all-around title in Paris, now trains her focus on the vault final, which again pits her against defending champion Rebeca Andrade.

The US superstar knows she faces serious competition from the Brazilian.

“I don't want to compete with Rebeca no more. I'm tired!” Biles said after she secured the all-around title. “It's way too close.”

Two boxers have found themselves embroiled in a gender controversy in Paris.

Taiwan's Lin Yu-ting won her opening bout on Friday and Algeria's Imane Khelif returns to the ring on Saturday after her 46-second opening win.

Both fighters were disqualified from the 2023 world championships, which were run by the International Boxing Association, after failing to meet “eligibility criteria”.

However, the International Olympic Committee has cleared the boxers to compete in the French capital, igniting a firestorm.

Hungarian boxer Anna Luca Hamori, who faces Khelif, wrote in a Facebook post: “In my humble opinion I don't think it's fair that this contestant can compete in the women's category.”

US pool queen

Ledecky, 27, powered to the 1500m freestyle title on Wednesday, adding an eighth gold medal to her glittering collection.

Australia's Ariarne Titmus stands in her way of winning a fourth straight 800m title.

Breakout star Summer McIntosh is targeting her third gold of the Games in the women's 200m medley.

The Canadian teenager has already collected golds in the 200m butterfly and the 400m medley in Paris, also taking silver in the 400m freestyle.

Rising star Zheng, who put out four-time French Open champion Iga Swiatek in the semi-finals of the women's singles, has a chance to make tennis history for China.

She takes on Croatia's Vekic on the same court where childhood inspiration Li Na wrote her name into history 13 years ago, becoming China's first Grand Slam champion at the French Open.

Saturday also features the men's cycling road race, with Dutch world champion Mathieu van der Poel, Paris Olympics time trail champion Remco Evenepoel and his Belgian compatriot Wout van Aert among the competitors.