DELRAY BEACH, Fla. (AP) -- Top-seeded John Isner needed only 79 minutes to beat sixth-seeded Kevin Anderson of South Africa 6-2, 7-6 (1) in the quarterfinals on a chilly Friday night at the Delray Beach International Championships.
Anderson is playing in his first tournament since right elbow surgery while in Melbourne during the Australian Open in January.
''Coming back from any surgery, especially right elbow surgery, is tough,'' Isner said. ''I don't think he had the RPM on his serve in the first set.''
While Isner raced through the first set, Anderson was in better form in the second set. Isner, who had 17 aces in the match, had 12 of those aces in the second set and three in the tiebreaker.
''The second set, I knew would be a battle so I just focused on my serve,'' Isner said. ''I couldn't serve any better than I did in the tiebreaker.''
Isner will play Edouard Roger-Vasselin of France in the semifinals. Roger-Vasselin defeated Ricardas Berankis of Lithuania 6-4, 6-3 in the quarterfinals.
Second-seeded Tommy Haas of Germany moved into the semifinals with a 7-6 (6) 2-6, 6-1 win over Ivan Dodig of Croatia.
The 19th-ranked Haas, who will turn 35 in March, is the oldest player ranked in the top 50.
''I'm not so worried about my age really, to be honest,'' Haas said. ''I worry about it when my birthday comes around and I recognize the fact I'm going to turn 35 and I'll celebrate it.
''When you're on the court competing against somebody that's 20, 25, 31, it doesn't matter. You're out there to compete and to try to win.''
Haas reached his 25th career final two weeks ago at the San Jose tournament, losing to Canadian Milos Raonic.
He's won 13 singles titles in his career - his last at Halle, Germany, last year where he beat Roger Federer in the final - and reached a career high No. 2 ranking in 2002.
Haas, who won the Delray Beach title in 2006, had to contend with chilly, windy, drizzly weather as well as a tenacious quarterfinal opponent.
Haas led 4-0 in the first set, but the 62nd-ranked Dodig won the next five games and was serving for the set at 5-4. Dodig dropped his serve in that 10th game on a third break point when he hit an unforced backhand long.
After Haas secured the first-set tiebreaker, Dodig took control of the second set. From 1-1 in the set, he won five of the next six games to even the score at one set.
Haas returned to control in the third set, winning every game but when Dodig served in the third game.
''I think the momentum went back my way in the third set and this time I played a little bit smarter than in the first set,'' Haas said.
Haas will play Ernests Gulbis of Latvia, the 2010 Delray Beach champion, in Saturday's semifinal. Gulbis beat fellow qualifier Daniel Munoz-De la Nava of Spain 6-1, 6-4.
''Everything was more of less good and there was nothing I didn't like about today's match,'' Gulbis said. ''It got a little bit easy for me because my opponent today couldn't get used to the speed and pace of the ball.''