Top seed Andy Murray suffered a shock defeat against Gilles Simon in the quarter-final of the ABN Amro World Tennis Tournament in Rotterdam.
The British number one and world number four lost 6-4 6-2 to the Frenchman, 15 places below him in the world rankings.
Murray, 27, lost his serve in the opening game and slipped up again in the fifth to concede the first set.
It was the same story in the second set with Murray failing to deliver on his first serve as he made many mistakes.
The Scot, who beat Canada's Vasek Pospisil 6-3 7-5 in the second round, had won 12 of the previous 13 meetings against the Frenchman.
Simon, seeded eighth, will face the Czech world number seven Tomas Berdych, who was a 6-1 6-4 winner against Frenchman Gael Monfils.
Stan Wawrinka also progressed to the last four in Rotterdam, defeating world number 37 Gilles Muller.
Number four seed Wawrinka sealed a 7-6 6-3 straight sets victory to set up a match against either Sergiy Stakhovsky or Milos Raonic.