Andy Murray will face Jiri Lehecka in the Qatar ExxonMobil Open semi-finals after beating French qualifier Alexandre Muller in three sets.
Murray hit back strongly after losing the opening set to win 4-6 6-1 6-2 in two hours and three minutes against Muller, who defied his world ranking of 170 early in the match.
The 35-year-old Scot, who knocked out German fourth seed Alexander Zverev in the previous round, was forced to produce some of his best tennis again as he stayed on course for his third title in Doha.
Murray told Amazon Prime in his on-court interview: “I had to start going for my shots a lot more.
“The first set I wasn’t doing enough with the ball and he was dictating a lot of the points and making me do a lot of running.
“I’ve obviously played a lot of tennis the last few days and that wasn’t going to give me the best chance to win the match, so I stepped up and started taking a few more chances.
“I was trying to come to the net when I got my opportunity and managed to turn it round.”
Murray beat Fernando Verdasco in the Doha final in 2017 – his last title before hip problems struck that summer – and now faces the Czech Republic’s world number 53 Lehecka, who upset top seed Andrey Rublev 4-6 6-4 6-3 earlier on Thursday.
Murray, currently world number 70, broke Muller’s opening service game to lead 2-0, but the qualifier went on to dominate the opening set with some outstanding heavy ball-striking.
The Scot, who was being out-hit from the baseline, spurned two break points at 3-4 down in the eighth game and Muller served out to take it 6-4 after 53 minutes as his level never dropped.
Murray appeared to get to grips with his opponent in the second set, taking the game to the Frenchman and breaking him twice to race 5-0 up.
Muller stemmed the tide by holding serve, but Murray was rewarded for his more aggressive approach as he took the second set 6-1 in 30 minutes to level the match.
In the decider, Murray was made to work considerably harder, but he maintained his intensity and produced some more brilliant tennis, breaking Muller twice more before sealing victory with an emphatic hold of serve.