Nadal looked to have regained his awesome clay-court prowess when sweeping away the opposition to win his sixth consecutive Monte Carlo Masters earlier this month to send an ominous message to his rivals with the French Open looming.

The Spaniard, who has dropped from top to third in the world rankings after an injury-hit 2009, should be well rested for his Rome title defense on his favorite surface after missing last week's Barcelona Open.
 

Colombian qualifier Santiago Giraldo, meanwhile, unleashed an arsenal of winners to upset former champion Juan Carlos Ferrero 6-0, 6-3.

The 76th-ranked Giraldo hit 32 winners to Ferrero's nine, and required only 17 minutes to win the opening set.

The 12th-seeded Ferrero won the Rome tournament in 2001 and entered with an 18-3 record on clay this season, but Giraldo came in on a run of his own, having beaten tour veterans Nicolas Lapentti and Jarkko Nieminen in qualifying.

Also, 14th-seeded John Isner celebrated his 25th birthday by rallying to beat Horacio Zeballos of Argentina, 4-6, 7-6 (5), 7-5.

Isner, the top American in the draw following Andy Roddick's withdrawal, hit 20 aces and faced only one break point - which he lost.

It was the 2.06-meter (6-foot-9) Isner's first win on clay this season, and the turning point came when a drop shot attempt from Zeballos hit the net to hand Isner his first break of the match and a 6-5 lead in the third set. The American then managed to shake off some nerves and finish Zeballos off on his third match point.

World number one Roger Federer, who has a bye to the second round like Nadal and the other top seeds, will start his campaign against Ernests Gulbis after the Latvian beat Cypriot Marcos Baghdatis 6-2 6-2.

In other matches, Italian wild card Paolo Lorenzi rallied to beat 31st-ranked Albert Montanes 2-6, 6-4, 6-3, and Philipp Kohlschreiber of Germany eliminated Pablo Cuevas of Uruguay 6-7 (1), 6-1, 6-4.

Later, Federer was set to play a rare doubles match with Davis Cup teammate Yves Allegro. The Swiss pair was to face Johan Brunstrom of Sweden and Jean-Julien Rojer of the Netherlands Antilles.

The top eight seeded players have first-round byes in singles.