Jack Draper retired from his first match of the clay-court season after struggling with what appeared to be a right knee injury.
Having opted to miss last week’s Monte Carlo Masters, Draper faced Argentina’s Tomas Martin Etcheverry in his first-round match in Barcelona on Monday.
After winning the first set, the Briton called a medical timeout when Etcheverry won the second set to level the match.
He received taping around his right knee but his movement was hindered and he lasted just five more games, with his coaching box urging him to quit from the match.
It is a blow to Draper, who retired down 4-1 in the third, ahead of his return to the Madrid Open, where he has a significant chunk of points to defend after reaching last year’s final.
Draper returned from a six-month injury lay-off in February before recording a fourth-round victory over Novak Djokovic at Indian Wells.
He lost to Reilly Opelka in the second round of the Miami Open before withdrawing from Monte Carlo to prioritise his recovery.
Draper struggled with a bone bruising injury in his left arm last season and is still managing his condition, but the knee issue appears to be a new one.
The British No 2 will be defending 650 ranking points, more than a third of his total points, at the Madrid Open later this month.
Draper reached a career-high No 4 in the world before Wimbledon last summer but could tumble outside the world’s top 40 if he doesn’t play Madrid.
