Top seed Roger Federer coasted into the quarter-finals of the Dubai Championships with a 6-3 6-4 victory against Marcel Granollers of Spain.The 29-year-old won in 70 minutes and now faces Sergiy Stakhovsky of Ukraine.Earlier Novak Djokovic took his winning streak in the tournament to 11 matches with a determined 6-3 2-6 6-4 win over Feliciano Lopez in one hour 48 minutes.The Australian Open champion, seeking a third successive Dubai title, will now play Florian Meyer in the last eight.Djokovic dominated the opening set but lost his serve early in the second as left-hander Lopez, who has lost all three of the meetings between the pair, found his range with his impressive forehand.Second seed Djokovic also made a total of 18 unforced errors and after a routine smash went into the net to give him set point, Lopez duly took the contest to a deciding set.Djokovic broke in the first game of that final set and though his opponent broke back, the Serbian secured another break of serve before moving 5-3 ahead courtesy of an ace and quickly closed out proceedings.“It was an exciting match, to be honest, even though I was struggling,” Djokovic said. “I don’t think I’ve played badly, actually. He played really well in the second set. I did make some unforced errors, but the match turned around and he felt the momentum and he was playing better than I did most of that second set.””But to be honest, I was a little bit surprised with the way he was returning. He was getting a lot of balls back and he was making me, you know, play an extra shot.”Federer, renowned for his exhibition-style shots between his legs, unveiled a magnificent over-the-shoulder lob in his routine victory over world number 53 Granollers.The four-time champion, who last took the title in 2007, was not entirely satisfied, however, and said: “I thought I had chances like in the first round to win it easier.”I think obviously the opportunity I had at 4-2, love-40 after playing such a good game, you know, I should have won that game and gone on to serve it out after that. But I was able to serve out regardless.”His next opponent Stakhovsky caused something of a surprise when he defeated eight seed Ernests Gulbis of Latvia 6-3 5-7 6-1 – BBC