Olympic gold medalist Zheng Qinwen extended her return to the US Open with a stunning comeback, winning the final seven games to eliminate No. 22 Madison Keys 1-6, 7-6 (3), 7-5 on Saturday. Amanda Anisimova, a past US Open runner-up, was also knocked out when No. 10 seed lost to No. 24 Anastasia Potapova 6-2, 7-5. Keys won a three-set match in the previous round in a match tiebreaker when she fought off five match points.

Two days later came a collapse that was as out-of-nowhere as that comeback. The 2017 runner-up rebounded after losing the second-set tiebreaker to charge out to 5-0 lead. Zheng held but Keys had a match point while serving at 5-1, and once she couldn't convert that, the turnaround was on, with Keys at one point banging her racket into her head repeatedly and pulling off her visor in disgust.

Anastasia Potapova, a 25-year-old who was born in Russia but now represents Austria, went 6-for-8 and matched her best showing in a Grand Slam tournament by reaching the fourth round. Anisimova missed repeated chances by converting just 3 of 16 break-point chances (19%).