Earlier, world No.1 Iga Swiatek overcame a shaky serving performance to beat American Jessica Pegula 6-3 7-6(4) and reach the semi-finals of the US Open for the first time.
The top-seeded French Open champion dropped her racket and pumped her fist after the win, which guaranteed that she will remain the world's top player when the tournament ends.
Despite the victory the Pole is still trying to regain her dominant form from earlier in the year when she went on a 37-match winning streak.
The 21-year-old twice failed to serve out the match in the second set and was broken six times by the eighth-seeded Pegula, who saw her own serve broken seven times.
Swiatek will meet Aryna Sabalenka in the semi-finals. She holds a 3-1 record against the powerful Belarusian.
Reuters.
