American Vincent Spadea upset holder Tommy Haas of Germany 6-3, 2-6, 6-4 to reach the semi-finals of the Delray Beach International on Friday.
Local favourite and number eight seed Spadea, who lives in neighbouring Boca Raton, was too strong for his second-seeded German opponent in a tight match at the $416,000 tournament.
Third-seeded Belgian Xavier Malisse thrashed Spaniard Guillermo Garcia-Lopez 6-1, 6-1 in the first quarter-final and will face Spadea in the last four on Saturday.
The American's win was a shock given his lowly world ranking of 63 against that of world number nine Haas.
Spadea, a Chicago native, hustled from the start to break Haas's resolve and serve, taking the first set in 40 minutes.
The German found his feet in the second set, breaking Spadea's second and third service games to level the match.
But Spadea responded by breaking Haas's third service game and, inspired by a noisy home crowd, won the match with an ace having served up three in his last four serves.
DOMINANT MALISSE
Number seven Garcia-Lopez, ranked 65th in the world, barely made an impression on Malisse, the world number 31, claiming only two service games during the match.
Malisse had only just scraped into the quarter-finals, a beneficiary of the round robin elimination method being trialled at various ATP tournaments this year starting in Delray.
The Belgian made the last eight with the second lowest aggregate winning percentage of the tournament, 56.9 percent, against Garcia-Lopez's 64 percent.
Malisse was in total control on Friday in the 80-degree heat of South Florida as he demolished his opponent.
Garcia-Lopez lost his first and second service games before regaining his composure to win his third service game but he was then broken again to hand the first set to Malisse.
The Spaniard had a more promising start to the second set when he won his first service game before being broken twice more, taking the score to 5-1.
That left Malisse needing to hold his serve to take the second set which he duly did as Garcia-Lopez powered a return into the net to lose the match in less than an hour.