Dubai - Stefanos Tsitsipas defeated Germany's Jan-Lennard Struff 4-6, 6-4, 6-4 on Thursday to set up a Dubai Championships semi-final against Dan Evans.
The two-hour and 23-minute duel, which allowed Greek second seed Tsitsipas to claim a seventh successive win, set the day's programme at the Aviation Club back by more than an 90 minutes.
It followed another lengthy struggle as Evans upset sixth seed Andrey Rublev 6-2, 7-6 (11/9) to reach the fourth ATP semi-final of his career.
World number 37 Evans said the thought of playing another set after more than two hours was just too much to consider and he worked hard to wrap up victory in straight sets.
"It was tough, I just hung in at the end and got through," unseeded Evans said.
"But I just didn't fancy playing another set. I think that's what got me through."
Tsitsipas trailed throughout most of the match against the 34th-ranked Struff, only taking the statistical lead late in the third set with a break for 5-4 which set up his victory.
"I was struggling with my return today, I don't know what was wrong with it," Tsitsipas said.
"I couldn't really find enough space to get that right momentum to hit the ball, that was the biggest struggle today.
"I'm actually pretty proud that I fought so hard, played with attention when I had to. When I got the break in the third set I knew that was my time to close the match now. I did it in perfect style."
Tsitsipas is defending his runners-up points from last year when he lost the final to Roger Federer.
He arrived in Dubai after winning the Marseille trophy at the weekend.
Struff reached the quarters after spending just 39 minutes in winning his previous match.
Top seed Novak Djokovic was playing his quarter-final later Thursday against Russian Karen Khachanov while number three Gael Monfils was squaring off with French compatriot Richard Gasquet.
Evans, 29, whose previous last four semi-final appearances came in Zagreb in 2014, Sydney in 2017 and Delray Beach a year ago, needed nearly two and a quarter hours to advance.
"Semi-finals in any tournament on the ATP Tour is great," he said.
Evans faced constant pressure from Rublev, who started this season with an 11-match win streak, lifting back-to-back trophies in Doha and Adelaide.
Evans needed to battle to earn the opening set, finally taking it after a final game in which he saved five break points before winning on his third set point.
The second set was equally intense. Evans was broken while serving for victory leading a set and 5-4, with Rublev taking it into a tiebreaker.
Evans missed on his first two match point chances before his opponent sent a return over the baseline to end the contest.
The victory was the second tight contest in a row for Evans, who saved three match points in the previous round against Frenchman Pierre-Hugues Herbert.
Evans was competing in a third quarter-final of 2020 after Adelaide -- where he lost to Rublev, the eventual champion -- and Rotterdam.