Li, who won the French Open last summer, looked favourite to come through when she recovered from losing the opening set to level but Robson did not waver and deservedly clinched a 6-4 6-7 (5/7) 6-2 win.

It was a hugely disappointing loss for Li, who has been one of the form players on the north American hard courts, and she felt she had contributed to her downfall.

She said of Robson: “She has a huge first serve. But it’s not like didn’t have a chance. I was making a lot of mistakes in the whole match, so I gave her a lot of free points. That made her like, ’Oh, I’ve got more confidence. Oh, I can beat her.”’

In the next round Robson will play another of last year’s grand slam winners, Stosur, who was given a tough time in the first set today by America’s Varvara Lepchenko before easing away to win 7-6 (7/5) 6-2.

Stosur said: “I think as the match went on I probably became a little bit more comfortable, got used to her spin and maybe the wind a little bit more.

“It was tricky out there during the first set and, when it’s tight, it’s hard to really kick-start something.

“I think once I got that first set then I maybe relaxed a little bit more. Once I got that break and then started to maybe see what was going on a bit more, it became a little bit easier for me.”

Marion Bartoli, the 11th seed, is also through to the last 16 after a 6-2 6-4 victory over fellow Frenchwoman Kristina Mladenovic.