Second-seeded Juan Martin del Potro retired in his first-round match against Somdev Devvarman of India after losing the first-set tiebreaker 7-6 (3) at the Dubai Championships on Tuesday.
Del Potro's been struggling with a left wrist injury and was having difficulty coming over the ball on his backhand during the 67-minute set.
The Argentine had three set points at 0-40 on Devvarman's serve in the 12th game, but the 78th-ranked Indian won the next five points to force the tiebreaker.
Devvarman, who won a challenger last week in New Delhi, hit a service winner on his third set point in the tiebreaker. That proved to be the final point of the match.
Third-seeded Tomas Berdych extended his winning streak to eight matches with a 6-3, 6-4 win over Romanian qualifier Marius Copil.