Second seed Andy Murray progressed to the second round of the Dubai Championships when Sergiy Stakhovsky retired with an ankle injury on Monday.
Murray was leading 6-7, 6-3, 5-3 and was 30-0 up on the Ukrainian's serve when, instead of trying to play out the final two points, Stakhovsky walked to the net to concede the match.
"I was surprised," the Briton told reporters. "It wasn't like there was a long time to go in the match.
"The first point of that game he was sliding to the backhand on the court. His ankle is obviously bad for him to stop but I would rather have finished the match.
"He hit two 190 (kph) serves to start the game so he was still serving okay. It seemed the movement to his forehand is where he was struggling but I've been in that position before and I always try to finish the match."
Murray had begun well, holding two points to take a 4-1 lead.
Stakhovsky, however, produced some nice touches and often controlled play from the middle of the court as he ran his opponent wide.
After levelling at 3-3 and an exchange of breaks in the next two games Stakhovsky went on to take the tiebreak 7-3.
Tending to win the longer rallies and looking tactically superior, the Ukrainian broke for a 1-0 lead in the second set but Murray responded by reducing his errors and taking the next four games.
In the final set the Scot won eight of the first nine points and games went comfortably with serve until Stakhovsky, who had injured his ankle late in the first set, retired.
"I started out very aggressively and was hitting the ball great and then I played a couple of bad games," said Murray of the opening set.
"When he broke me in the second set I was always getting chances on his serve and knew I was going to have the opportunity to get back in the match."
It was a difficult day for all four seeds in action and one went out.
Fourth seed David Ferrer of Spain defeated Croatia's Ivan Ljubicic 3-6, 6-2, 6-1 and fifth seed Marin Cilic of Croatia came from behind to beat Serbian Janko Tipsarevic 2-6, 7-6, 6-4.
Croatian Ivo Karlovic, seeded seven, lost 7-6, 4-6, 7-6 to Swiss qualifier Marco Chiudinelli.