PARIS - Novak Djokovic dispensed with the Darth Vader mask but still proved too daunting an adversary for American John Isner as he reached the Paris Masters quarter-finals with a 6-7(5) 6-1 6-2 victory on Thursday.

The Serbian world number two, who entered the Bercy arena last year as the infamous Star Wars villain, survived a barrage of aces from the towering Isner before ruthlessly dispatching him.

Novak Djokovic of Serbia servesl to John Isner of the U.S. at the Paris Masters men's singles tennis tournament at the Palais Omnisports of Bercy in Paris, October 31, 2013. [Photo/Agencies]

"I know, I know. It's my fault. I was not prepared enough ... so I'm going to have to be pretending that I'm myself this year. No Darth Vader," Djokovic, who watched nine aces fly by him in the opener, told a news conference.

Roger Federer showed glimpses of his brilliant best as the 17-times grand slam champion outclassed German Philip Kohlschreiber 6-3 6-4 to advance into the last eight.

A day after securing his place at next week's ATP World Tour finals, the Swiss was comfortable throughout as he set up a clash against Juan Martin del Potro who beat him in the Basel final last week.

Canadian Milos Raonic, who still has a glimmer of a chance of snatching one of the last two qualifying spots for the London season-ender, was up against Czech sixth seed Tomas Berdych later.

The best-placed in the race is Djokovic's next opponent, Swiss seventh seed Stanislas Wawrinka, who almost secured his place with a 6-3 6-2 dismissal of Spain's Nicolas Almagro.

"Almost means it's not yet done, but it's always a good thing to win those matches and of course to become closer to go to London," the Swiss told a news conference.

"Either I win one more match or the others lose before I do, or before the final for Raonic.

"Anyway, I'm very pleased for this match today, because not only am I playing to qualify for London, but I want to play and have a good tournament here in Paris."

Wawrinka is eighth place in the ATP Race to London ahead of Richard Gasquet (9th) and Raonic (10th).

The cut was lowered to ninth place after British world number four Andy Murray pulled out of the London finale because of a lower back surgery.

Spaniard David Ferrer, already assured of his place in London, continued his bid to become the first man to retain the Bercy title by demolishing France's Gilles Simon 6-2 6-3.