Spain's Nicolas Almagro hammered top seed David Nalbandian 6-1, 7-6 (7-1) to win the Acapulco International tournament, ending the Argentine's 10-match unbeaten run.
Almagro's powerful serve proved too much for Nalbandian, who was attempting to win his second tournament in a row on Saturday night after his victory in Buenos Aires last week.
The Spaniard, seeded sixth, took one hour 25 minutes to clinch the fourth ATP title of his career.
"I based my game on my serve and my aggressive tennis," he said. "These have been my keys as well as my winning attitude."
Almagro dropped only 13 points in the first set and, although Nalbandian put up more of a fight in the second, he committed too many unforced errors and forced only two break points, neither of which he won.
"It didn't work out," he said. "Nico played a good game and is a great winner."