Andy Roddick had three match points to beat Kevin Anderson on Friday, but could not convert any and the South African won through to the semifinals of the Delray Beach International Series.
Seventh-seeded Anderson won 2-6, 7-6 (9), 6-4 to set up a semifinal against another big-serving American, John Isner.
"There's not often I can look back at my career and say a serve lost me the match," Roddick said. "But, today, that was the case.
"I've made a career of getting my first serves in."
Isner advanced with a solid 6-3, 6-2 victory over No. 8 seed Bernard Tomic of Australia. On the other half of the draw, Dudi Sela of Israel progressed to a rare semifinal berth by beating Germany's Philipp Kohlschreiber 6-4, 6-7 (4), 6-0, and will face Australian qualifier Marinko Matosevic, who finished strongly to beat Ernests Gulbis of Latvia 3-6, 6-1, 6-1.
Despite the loss, Roddick feels his game is getting into better shape after dealing with a right hamstring and right ankle injury this season.
"I played OK this week," Roddick said. "I returned a little bit better. I flowed a little bit better than a week ago. It's just a matter of getting my percentage better on my serve."
On a day where the swirling wind annoyed all players, Isner put up nine aces and won four of his nine service games at love in the 56-minute match.
"I played well right from the get-go," Isner said. "When he has time, that's when he gets comfortable. So I wanted to keep the points short, which is what I want to do every match.
"The wind was very, very tricky."
The 75th-ranked Sela reached his first ATP World Tour semifinal since the 2010 Chennai tournament.
Sela was serving for the match in the second set and was up 30-0 but lost the next four points to send the second set into a tiebreaker which Kohlschreiber won. The Israeli was more ruthless in the third set, losing only four points in his three service games.
"I was supposed to win in two sets," Sela said. "I was 6-5 in the second set, 30-love serving, and I got a little nervous and he went for two good shots.
"But I'm happy I played well in the third, stayed positive and won the match."
The 173rd-ranked Matosevic, who is currently on an 11-match winning streak, is into his first career ATP semifinal.
"It feels good, especially coming through qualifying because it feels like I really earned it," Matosevic said. "The conditions were really tough and the wind was really getting me down in the first set. I just wasn't making enough balls and returns.
"I just let him beat himself in the end."