The momentum swung one way and the other as the set progressed, and seven more double faults certainly didn’t help the Williams cause. The second seed earned herself a break to lead 3-1, but immediately undid her good work by serving four double faults in the very next game.

Peng managed to break back, but that was the last game she won. Her unforced errors, particularly on the backhand side, proved to be her undoing, and it was one such mistake on match point that gifted the American a spot in the last eight.

“I made errors, but one has to move on, stop thinking about the last shot, whether it was good or bad. The ball bounces higher here, and is a bit unpredictable, but I felt I had the upper hand,” said Venus.

“I would have loved to close it out in two sets, but she played really well,” she admitted.

Meanwhile, the only thing that bothered top seed Jelena Jankovic was a stubborn insect that refused to leave the court. Barring that, she had little trouble packing off Croatia’s Sanda Mamic, her impeccable groundstrokes paving the way for a 6-2, 6-2 victory. And in another match, China’s Zi Yan defeated Ukraine’s Olga Savchuk 6-2, 6-1.

Doubles results: Chunmei Ji/Shengnan Sun (CHN) bt Akgul Amanmuradova (UZB)/Olga Savchuk (UKR) 6-3, 7-5; Ekaterina Dzehalevich (BLR)/Monica Niculescu (ROU) bt Yaroslava Shvedova/Anastasia Rodionova (RUS) 6-7, 6-3, 10-8