The scores were 5-7, 6-4, 6-4, 6-4, in a match that lasted nearly five hours.
Nadal, the defending men's champion, was celebrating his 20th birthday. He extended his record clay-court winning streak to 56 matches -- with his last loss on clay coming on April 8, 2005, against Igor Andreev of Russia.
Before it got too dark too play, No. 4 Ivan Ljubicic of Croatia was leading Juan Monaco of Argentina, 4-6, 5-7, 6-3, 6-4, 4-2; and No. 8 James Blake of the United States was tied with Gael Monfils of France, 2-6, 7-6 (7-2).