Maria Sharapova fought Klara Zakopalova as well as swirling winds for more than three hours to book her place in the French Open quarter-finals with a 6-4 6-7 6-2 win over the unheralded Czech on Monday.
The Russian second seed, looking to complete her collection of grand slam titles, spent more time on court on Monday than she had in total over her three previous matches.
The windswept conditions on Court Philippe Chatrier made it almost impossible for the players to throw the ball and a total of 21 games, 17 of them in the first two sets, went against serve.
Sharapova, who will take over as world number one if she reaches the final, eventually stamped her authority on the match in the final set to set up a last-eight meeting with either Dutchwoman Arantxa Rus or Estonian 23rd seed Kaia Kanepi.
Champion Li Na's title defence ended when she was knocked out in a flurry of unforced errors by Kazakh qualifier Yaroslava Shvedova 3-6 6-2 6-0.
After taking the first set, the Chinese seventh seed collapsed, taking only two games out of the next 14.