Britain's Kyle Edmund is still waiting for his first ATP win this year after losing to Dominic Thiem in straight sets at the Madrid Open.
Edmund, 28, has now lost all six games on tour in 2023 after Austria's Thiem enjoyed a 6-4 6-1 first-round win.
The Briton forced two break points in each set but failed to take advantage and was beaten inside 82 minutes.
Former world number 14 Edmund is recovering from two knee operations and is currently ranked 498th in the world.
Thiem won the US Open in 2020 but the former world number three is also coming back from injury and has dropped to 93rd in the rankings.