ROME — Six-time champion Rafael Nadal overcame one of the worst opening sets of his career to edge Latvian qualifier Ernests Gulbis 1-6, 7-5, 6-4 Thursday and reach the Italian Open quarterfinals.
Nadal's performance, and sometimes sluggish movement on the court, raised questions about whether he will be able to successfully defend his title at the French Open. The year's second Grand Slam starts in 10 days.
Nadal will next face fourth-seeded David Ferrer, who advanced when Philipp Kohlschreiber of Germany withdrew because of dizziness.
Top-ranked Novak Djokovic had a far easier time than Nadal, beating Alexandr Dolgopolov 6-1, 6-4 to improve his clay-court record this season to 8-1. Serena Williams routed 14th-seeded Dominika Cibulkova 6-0, 6-1 for her 21st consecutive win, matching the best streak of her career.
Nadal, however, was far from his best, especially in the first set, in which Gulbis jumped to a 5-0 lead and even had a point to close out the set at love.
But Nadal, who has reached the final in all seven tournaments he has played since returning to the circuit in February from a seven-month break because of a left knee injury, eventually began to win the longer points while the carefree Gulbis started to commit more errors.
The only men's seed to lose was No. 7 Juan Martin del Potro, who was beaten by 36th-ranked Benoit Paire of France 6-4, 7-6 (3).
Elsewhere at the Foro Italico, two-time champion Jelena Jankovic edged fifth-seeded Li Na of China, 7-6 (2).