Volkswacht Bodensee - Alcaraz dumped out by Lehecka in Qatar Open quarters

The top seed dropped the first set before recovering to level, and then led by a break in the decider, but world number 25 Lehecka won the final four games for a 6-3, 3-6, 6-4 victory.

Alcaraz entered the clash on a seven-match winning streak following his triumph in Rotterdam earlier this month but ran into trouble against a confident Lehecka, who won his second career title in Brisbane to start the year.

"I feel great," said Lehecka. "To win a match like that against a player like this is a super big achievement. I believed in myself and knew I had the level to produce this kind of tennis.

"I think the most important part was I believed in my game and did not back down."

The 23-year-old Czech will play British eighth seed Jack Draper or Italy's Matteo Berrettini on Friday for a place in the final. Lehecka is through to the last four in Doha for the second time.

Berrettini, a former world number six and Wimbledon runner-up, knocked out Novak Djokovic in the second round.

Andrey Rublev converted his eighth match point against De Minaur to take his place in the semi-finals.

The Russian, a Qatar winner in 2020, had to dig deep to down the Australian 6-1, 3-6, 7-6 (10/8).

Fifth-seeded Rublev let slip a 5-2 lead in the final set as De Minaur scrambled back into contention to force a tiebreak.

Rublev finally got over the line, the 27-year-old saving a match point himself in a memorable quarter-final clash.

"When I had my first match point, I played really well," said Rublev.

"I did everything amazing and he just played an unreal rally. He made the backhand down the line and I played a good volley.

"Then he makes a forehand pass down the line. In most of the matches, normally after these points, they win - it's a turning (point).

"I then started to get a bit more tight and more emotional, I was a bit unlucky. Then when I lost my serve, I said 'Okay, whatever, if I'm gonna lose, at least just try to do your best until the end'."

This was his first win against a top-10 player since August last year.

Rublev's reward for his fourth semi-final appearance in Qatar was a meeting with Felix Auger-Aliassime.

The Canadian was leading his quarter-final against Daniil Medvedev 6-3 when the Russian had to retire.

M.Betschart--VB