Novak Djokovic reached the Dubai Championships final, rallying past fourth-seeded Juan Martin del Potro 6-3, 7-6 (4) Friday in a match that turned after a time violation warning.
Djokovic will face either defending champion Roger Federer or third-seeded Tomas Berdych.
The top-ranked Serb, bidding for his fourth Dubai title in five years, made the only break of the first set and won it when del Potro hit a return long. Del Potro then took a 3-0 lead thanks to a much-improved service game only to unravel when he was warned for taking too long on his serve.
Serving at 3-1, 30-40, the Argentine was given a warning by the chair umpire for taking more than the allotted 25 seconds. It sparked a flurry of boos in the packed stadium and an angry del Potro hit a forehand wide to make it 3-2. Djokovic ran off the next three straight games and seemed in control. But with the Serb up 5-3 and serving for the match, del Potro broke a second time and made it 5-all.
Djokovic forced the tiebreaker and won it when del Potro hit another forehand long.
Del Potro said he lost his focus after the warning for the time violation.
"I lost my calm when I started to discuss with the umpire, and (Djokovic) come back in the second so quick," del Potro said. "He's the No. 1. When he feels the chance to improve his game, he always takes it. Tonight, he played better all the time."
Del Potro criticized the timing of the warning, considering it came just as he was ready to serve. His complaints followed that of Berdych, who said this week it was an unnecessary rule and a clock should be put on court to ensure the rule was consistently applied.
"We play very long rallies during the match and he called the warning just before I served, a break point down," del Potro said. "It's a very important point for the game, for the match. Maybe he doesn't know about that. ... If you call a warning or if you do something different, you can lose focus, and that's what happened with me."
Djokovic agreed it was an unfair call because del Potro had not been privately warned beforehand, which often is the custom.
"As a chair umpire, you need to follow the game," Djokovic said. "If it's a long point, you need to have that little amount of tolerance, I guess, and patience also for the player. It's unfortunate obviously, you know. I understand why he was frustrated."
The ATP modified the rule this year to make it easier for umpires to crack down on slow play. Slow play between points has been a long-running complaint among fans and some players.