ACAPULCO, Mexico -- Unseeded Alessio Di Mauro upset top-seeded Guillermo Coria of Argentina on Tuesday, 6-2, 6-4 in the first round of the Mexican Open.
In women's play, defending champion Flavia Penetta of Italy cruised through her first match, eliminating compatriot Antonella Serra Zanetti 6-4, 6-2.
Coria won his first two service games but was broken in his third and fourth, double faulting several times and losing the set on the clay courts of the Fairmont Acapulco Princess in just 31 minutes.
He tried to rally in the second set but lasted only another 52 minutes before more double faults proved decisive.
"I'm playing badly. Not just in this game but all year," Coria said. "I thought I could change the situation today, but it was very difficult. The court is very fast, and [Di Mauro] took advantage of his opportunities."
In other matches, Spaniard Alberto Martin toppled fourth-seeded Felipe Volandri of Italy 6-0, 2-6. 6-2.
Also on Tuesday, Argentine Agustin Calleri toppled Nicolas Lapentti of Ecuador 6-3, 6-3.