Jannik Sinner reached the fourth round of the U.S. Open, avoiding the fate of his main rivals, while fellow top seed Iga Swiatek gained momentum in her bid for a sixth Grand Slam title after a pep talk from Serena Williams on Saturday.

With defending champion Novak Djokovic forced out by a shock loss to Alexei Popyrin in the third round on Friday and another title contender, Carlos Alcaraz, stunned by Botic van de Zandschulp in the second round a day earlier, all eyes were on Sinner.

The Italian, who has managed the intense scrutiny following a doping controversy in the build-up to the tournament, thumped Christopher O'Connell 6-1, 6-4, 6-2 to underline his status as the outright favorite at the year's final major.