No. 2 Nicolas Almagro of Spain beat Potito Starace of Italy 4-6, 6-3, 7-6 (4), at Copa Claro clay-court event on Tuesday.
Gilles Simon of France defeated Rui Machado of Portugal 6-3, 7-5, and No. 5 Juan Monaco of Argentina advanced when Filippo Volandri of Italy retired in the second set with an injury. Monaco was leading 6-1, 3-1.
Top-seeded David Ferrer of Spain had no trouble beating Argentine Andres Molteni 6-1, 6-0.
"I'm happy to get out of the first round, and I think he (Molteni) was a little nervous," Ferrer said.
Molteni had plenty of support from local fans, who were hoping for some revenge for Spain's victory over Argentina last year in the Davis Cup final at Seville, Spain.
"I like fans supporting the local players," Ferrer said. "It's the normal thing to do, and personally I like it."
Seventh-seeded Fernando Verdasco of Spain defeated Eric Prodon of France 6-4, 6-1.
Juan Ignacio Chela of Argentina was upset by Albert Ramos of Spain 4-6, 6-3, 6-4.
In other matches, Benoit Paire of France defeated Javier Marti of Spain 2-6, 7-6 (0), 6-2, and Igor Andreev of Russia stopped Blaz Kavcic of Slovenia 6-2, 6-2.