LONDON: Novak Djokovic won the battle of grand slam champions by downing Marin Cilic 6-4 6-4 6-4 to reach his sixth straight Wimbledon semi-final on Wednesday and was relieved to conserve his energy for the challenges ahead.

He will face Richard Gasquet in the last four after the Frenchman with the backhand to die for overcame French Open champion Stan Wawrinka in five gripping sets.

Top seed Djokovic himself got an almighty scare in the last 16 when he went two sets behind to South African Kevin Anderson and must have expected another tough encounter against U.S. Open champion Cilic but in the event it was a walk in the park.

The Serb had not lost to the Croat in 12 previous meetings and his unbeaten record never looked in danger against an opponent who failed to master Djokovic's precise groundstrokes.

The holder made it into his 27th grand slam semi with his 50th Wimbledon win, only the seventh man to reach that number of victories, and was surely relieved to have an easy time of it.

The world number one's crisp passing shots ensured big-serving ninth seed Cilic never got a look in on Centre Court.

"I didn't know how my body was going to feel but I was hoping I would play well, which I have done," said Djokovic, who was playing for the third day running after his contest against Anderson spilled over into a second day.

Djokovic broke in the third game of the first set, the ninth game of the second and the seventh game of the final set to wrap up victory inside two hours on a cool London evening.

"I managed to make three decisive breaks in each set. I came out with the right intensity, moved well all over the court, tried to get as many returns back in play," he said.

Cilic made too many unforced errors and, though he successfully tried to serve and volley early on, he relied on his booming serve and powerful groundstrokes.

The trouble was that Djokovic outclassed him in both departments and when Cilic tried to mix it up, his dropshots invariably fell short and his volleying eventually went awry.

Djokovic believes he has had his blip against Anderson and can now produce his best at the business end of the tournament.

"I'm hoping I have that extra gear. I'm hoping it can come out now in the semi-finals, the most important matches, the final stages of the tournament," he said.