Britain's Andy Murray reached his first ATP semi-final in eight months by beating French qualifier Alexandre Muller at the Qatar Open.
Murray, 35, fought back to win 4-6 6-1 6-2 against 26-year-old Muller, who was playing in his first ATP quarter-final.
The Scot will play Jiri Lehecka in the last four after the 21-year-old Czech beat top seed Andrey Rublev.
"He is one of the best young players on the tour, it'll be a big test for me," said former world number one Murray.
"He has started the year extremely well, did well at the Australian Open and hits a huge ball.