(Xinhua/AFP Photo) 

    ROME, May 11 (Xinhuanet) -- Top seed Serena Williams had to labor in her opening campaign at the Rome Masters Tuesday as the American managed a 7-5, 6-3 victory over Maria Sanchez-Lorenzo in the second round.

    2001 champion Jelena Dokic of Serbia and Montenegro suffered a blow as she lost 7-5, 7-5 to Italian wildcard Maria Elena Camerin to the delight of the crowd on center court.

    Russian sixth seed Elena Dementieva became the other big-name casualty of the day, going down 6-1, 6-4 to compatriot Maria Sharapova.

    Williams committed a series of mistakes Tuesday, flailing groundstrokes wide and into the net to gift break points to the Spaniard, who finally won it at the sixth attempt when Williams pushed a forehand into the tramlines.

    The top seed struck back to take the first set, but again had to come back from a break behind in the second.

    In the third round, Williams faces the winner of Wednesday's match between qualifiers Vera Douchevina and Dally Randriantefy.

    Having won on her comeback at the Masters event in Miami from an eight-month layoff, Williams then suffered her heaviest defeat in five years, a 6-2, 6-3 loss to Russia's Nadia Petrova, in her next tournament at Amelia Island.

    She then withdrew from last month's event in Charleston citing an inflammation of the knee that had given her so many problems inthe past, but on Monday had insisted she felt fit enough to repeather Rome triumph of 2002. Enditem