It can't get better than this. A repeat of this year's Australian Open semi-final and six Dubai titles split between them in the 19-year history of the event. Really, it can't get any better than when two-time reigning champion Novak Djokovic takes on former four-time winner Roger Federer for the sixth time in as many times to decide the Dubai Duty Free Men's Open champion on centre court on Saturday. To start with, history will not side either of the two. Federer has won the crown four times in the past seven occasions that he's played here - 2003, 2004, 2005 and 2007, while finishing runner-up to Rafael Nadal in 2006. The other two times, Federer lost in the second round [against Rainer Schuettler] and to Murray in the first round in 2008. On the other hand, Djokovic is on a roll. He is on a 13-match winning streak at the ATP World Tour level play going back to last season when he posted two wins in the Davis Cup against France. Ironically, his last loss came to Federer in the semi-final of the Barclays ATP World Tour Finals at the O2 Arena in London at the end of November 2010. In his fifth consecutive appearance, Djokovic lost in the quarter-finals in 2007 [against Federer] and then fell in the semi-finals to Andy Roddick in 2008. Since that loss, the Serb has won 14 straight matches here helping himself to the titles in 2009 and 2010. And yesterday, both of them were nearly at their very best: Djokovic escaping after third seed Tomas Berdych retired with an injury, while Federer turned tutor for unseeded Frenchman Richard Gasquet with a 6-2, 7-5 domination. Djokovic was on serve and leading 4-2 in the third set when Berdych pulled out due to a bothersome quadriceps that was restraining his movement on court. The Serb was bemused with his display especially in the first set that he lost in the tie-breaker. "I don't know how to explain this match, but this was definitely the worst one I have played this season," Djokovic later rued. Earlier in the first of the doubles semi-finals, Sergiy Stakhovsky and Mikhail Youzhny got the better of Marcel Granollers and Dick Norman 6-3, 6-4. Results: Singles semi-finals: Roger Federer bt Richard Gasquet 6-2, 7-5; Novak Djokovic bt Tomas Berdych 6-7 (5), 6-2, 4-2 (retd.). Doubles semi-final: Sergiy Stakhovsky/Mikhail Youzhny bt Marcel Granollers/Dick Norman 6-3, 6-4.