Croatia's Ivan Ljubicic upset third seed Tim Henman 7-5, 6-4 in a match disrupted by rain to reach the semi-finals of the Dubai Open on Friday.
Spanish fifth seed Tommy Robredo defeated Nicolas Kiefer 6-4, 6-4 in the only other match to be completed and will meet Ljubicic next.
The quarter-finals involving world number one Roger Federer and fourth seed Andre Agassi were postponed until Saturday. The semi-finals will be played in the evening.
Henman and eighth-seeded Ljubicic had to come on court seven times before completing their match in six hours 45 minutes. At times they did not even get as far as re-starting play before having to come off court again.
"It's disappointing to play a match of this nature when I couldn't have been happier with the way I played in my two previous matches," said Henman, who has lost the last four of his five meetings with 25-year-old.
"To finish the event on this sort of note is not something I would have wished. I felt like I had a good opportunity and that I'd played a couple of really good matches, and I was ready to build on that.
"But I felt that each time we re-started it took me longer to find my rhythm, and he doesn't give you much rhythm anyway. He serves so aggressively," added the Briton.
Henman failed to win two break points at 2-2. He did well to fight off three break points as Ljubicic led 4-3 but wasted his good work after play re-started at 5-5 when he double-faulted and hit a tame forehand into the net to concede the first set.
Although Henman broke to lead 1-0 in the second set, Ljubicic forced a backhand error to level at 3-3 before breaking again for the match with a winning return.
