France's Sebastian Grosjean showed he is returning to form with a 7-5 4-6 6-2 win over Feliciano Lopez in the first round of the Madrid Masters.
Meanwhile, Victor Hanescu of Romania overcame Czech Tomas Zib 6-1 6-4 to set up a clash with top seed Rafael Nadal.
Argentinian duo Agustin Calleri and Juan Ignacio Chela breezed into round two with straight sets victories.
Calleri disposed of Spain's Albert Costa 6-0 7-5 while Chela beat 2003 finalist Nicolas Massu 6-2 6-3.
Eleventh seed David Ferrer of Spain will be Calleri's next opponent and Chela meets Austria's Juergen Melzer, who defeated American Vince Spadea 3-6 6-4 6-3.
British number one Tim Henman faces America's Taylor Dent in his first-round match later on Monday.