Britain's Andy Murray roared into the quarter-finals of the Dubai Championships with a comfortable 6-2, 6-3 win over Arnaud Clement of France on Wednesday, but top seed Novak Djokovic was made to toil for his place.
Second seed Murray broke to love to lead 2-1, and then held off two break points with aces at 3-2 before breaking again to lead 5-2.
An early break for 2-1 when Clement netted a backhand quickly gave him the advantage in the second set, and he broke again for the match with a forehand winner.
"I served very well in comparison to my last match," Murray told reporters. "I was pushing out much better for my serve.
"I managed to dictate the match with my serve. I didn't give him many chances after my first couple of service games, and I obviously managed to get into a lot of his service games and put a bit of pressure on him, and he made some mistakes."
Murray will now face another Frenchman, Richard Gasquet, who needed over three hours to overcome Simone Bolelli of Italy 6-7, 6-3, 7-6.
Djokovic took more than two hours to defeat Czech Jan Hernych 6-3, 3-6, 6-4.
The Serbian world number three was never able to dominate an opponent who rallied well and played more consistently.
After a single break decided each of the first two sets, Hernych broke to lead 2-1 in the third. But Djokovic immediately levelled at 2-2, and broke again in the final game with a forehand volley down the line.
"I played well in the first set and had a couple of break points at the start of the second, and suddenly I started breaking up," said Djokovic.
"I was too defensive, I had a lot of ups and downs and allowed him to come back into the match. But it's important, matches where you don't play well or you don't feel well on the court, but you win. That is what matters."
French third seed Gilles Simon took just 53 minutes to crush Russia's Teimuraz Gabashvili 6-1, 6-2, and fourth-seeded Spaniard David Ferrer also progressed smoothly with a 6-4, 6-2 victory over Philipp Kohlschreiber.
Fifth seed Croatian Marin Cilic lined up a clash with Djokovic by edging Julien Benneteau of France 6-3, 4-6, 7-5, and sixth seed Igor Andreev defeated Dmitry Tursunov 5-7, 6-4, 6-3 in an all-Russian clash.