DUBAI  - Novak Djokovic won his fifth title in six tournaments and his 36th altogether, and extended his unbeaten run to 18 matches as he regained the Dubai Open title with a 7-5, 6-3 win over Tomas Berdych.The world number one from Serbia underlined his pre-eminence in the world game with a thoughtful as well as athletically aggressive performance against the world number six from the Czech Republic, who the night before had knocked out Roger Federer, the titleholder. Berdych made the first break and had chances to take control of the first set but Djokovic often provoked errors by subtlely making Berdych generate his own pace, and counter-attacked brilliantly.Perhaps Djokovic's worst moment was when he was given a time warning by the umpire at deuce when he was serving for the match, but the incident hinted at the strength of his temperament which was a major factor in the triumph. "It's a thrilling feeling to prevail in the end in a great tournament like this," said Australian Open champion Djokovic after claiming a fourth Dubai title. "Tomas is a fantastic player and he beat Federer in an incredible match. It was very close today and could have gone either way."