(FILES) In this file photo taken on June 6, 2021, Serena Williams of the US reacts as she plays against Kazakhstan's Elena Rybakina during their women's singles fourth round tennis match on Day 8 of The Roland Garros 2021 French Open tennis tournament in Paris. - Serena Williams hopes of a record-equalling 24th Grand Slam title took another hit on August 25, 2021, when she announced on her Instagram page that she was pulling out of next week's US Open because of a hamstring injury. (Photo by Christophe ARCHAMBAULT / AFP)