The second-seeded Swede, last year's French Open runner-up, next plays Argentine Eduardo Schwank who put out Spain's Ivan Navarro 6-3, 7-6.

Third seed Jo-Wilfried Tsonga and number five Fernando Verdasco had to come from behind to advance.

Frenchman Tsonga overcame Spain's Nicolas Almagro 5-7, 6-1, 6-4 while home hope Verdasco beat Austrian Juergen Melzer 3-6, 7-6, 6-3.

World number 10 Tsonga will play Thiemo de Bakker for a place in Saturday's semifinals after the 21-year-old Dutchman upset seventh seed Juan Carlos Ferrero 7-6, 3-6, 7-6.
"I wasn't sliding well at the start, the clay was quite heavy," Tsonga told reporters.

"Then I started to play a bit more how I play on hardcourts which enabled me to get back into the match in the second and third set."

Verdasco, losing finalist at last week's Monte Carlo Masters, will play Ernests Gulbis on Friday after the Latvian saw off Spanish qualifier Albert Ramos 6-1, 6-3.

"I have to prepare for tomorrow's match now which is definitely going to be very tough."
Spanish eighth seed David Ferrer, runner-up to compatriot Rafael Nadal in 2008 and 2009, advanced when Simone Bolelli retired from their match with a wrist injury.

World number 17 Ferrer was leading 6-0, 3-0 when the Italian pulled out. He next plays Thomaz Bellucci after the Brazilian 13th seed beat Spain's Guillermo Garcia-Lopez 6-4, 6-4.

World number three Nadal, who has won the title for the past five years, skipped this week's event to give his body a rest after landing a record sixth consecutive Monte Carlo crown on Sunday.