World number one Karolina Pliskova played down an arm injury after fighting back to beat China’s Shaui Zhang in the US Open third round.
World number 26 Zhang had match point at 5-4 in the second set, but Pliskova turned it around to win 3-6 7-5 6-4.
The result means she stays in the race with Elina Svitolina and Garbine Muguruza to end the tournament as number one.
“I feel much better,” said the Czech, who had treatment after the second set.
“I did some recovery and just saw the physios and some ice bath and those stuff. Hopefully it will be fine, it just felt a little bit tight during the match.”