John Isner advanced to the semi-finals by avenging a loss to defending champ Kevin Anderson at the ATP Tour's Delray Beach Tennis Championships on Friday.
Top seed Isner won in straight sets, beating South Africa's Anderson 6-2, 7-6 (7/1) in one of four quarter-final matches that featured three formers winners.
Isner, who is the last American left in the draw, hammered 17 aces, had one double fault and won 85 percent of his first-serve points in the 79-minute match.
Isner moves to the semi-finals where he will face France's Edouard Roger-Vasselin who cruised past Ricardas Berankis 6-4, 6-3.
Anderson beat Isner in the semi-finals last year before going on to win the title. Isner has now won five of eight career meetings with Anderson.
Anderson was playing in his first tournament since undergoing right elbow surgery January 21.
German second seed Tommy Haas outlasted Croatia's Ivan Dodig 7-6 (8/6), 2-6, 6-1 to reach the semi-finals.
Haas, 34, is a former World No. 2 now ranked 19th who is seeking his 14th career title in the Florida hardcourt event.
Former champion Haas will next face Latvian qualifier Ernests Gulbis, who defeated Spanish qualifier Daniel Munoz 6-1, 6-4 in 75 minutes.
The Delray Beach event is the final tuneup for next week's start of the ATP Masters Series tournament at Indian Wells, California.