* Nadal downs last year's runner-up Janowicz
* Gasquet, Wawrinka complete Tour finals lineup
* Djokovic also through to last eight (Recasts after Nadal wins)
PARIS, Oct 31 (Reuters) - World number one Rafa Nadal broke the stubborn resistance of Poland's Jerzy Janowicz's to win 7-5 6-4 and reach the last eight of the Paris Masters on Thursday.
In the semi-finals of the Paris event - one of only three Masters titles the Spaniard has yet to win - Nadal faces local favourite Richard Gasquet who, along with Swiss Stanislas Wawrinka, have completed the ATP World Tour finals lineup.
Both players won their third-round matches at Bercy but it was Canadian Milos Raonic's defeat by Tomas Berdych that sent them into next week's season-ending showdown in London.
They join Nadal, Novak Djokovic, David Ferrer, Juan Martin del Potro, Berdych and Roger Federer in next week's showpiece. All eight reached the Paris Masters quarter-finals on Friday.
World number two Djokovic and 17-times grand slam champion Roger Federer, who is ranked sixth, also advanced.
Nadal, who has yet to win the Miami and Shanghai Masters either, broke decisively in the 11th game of the opening set and, after an early trade of breaks in the second, got the upper hand when he took Janowicz's serve again in the fifth game.
The Pole, who broke into the limelight by reaching last year's final at Bercy where he lost to Ferrer, contained his frustration but Nadal's top spin was eventually too much to handle.
Djokovic dispensed with his Darth Vader mask and proved too strong for American John Isner in a 6-7(5) 6-1 6-2 victory.
The Serbian, who entered the Bercy arena last year imitating the infamous Star Wars villain, survived a barrage of aces from the towering Isner before ruthlessly taking him apart.
"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.
Federer showed glimpses of his brilliant best as he outclassed German Philip Kohlschreiber 6-3 6-4 to advance.
A day after securing his place at the World Tour finals, the Swiss won comfortably to set up a clash with Argentine Juan Martin del Potro, who beat him in the Basel final last week.
"It wouldn't be nice to lose once more against him. If it happens I will accept it, but if I win I will have something extra for London," Federer told a news conference.
"I have an idea of my tactics, my gameplan. Now it's important to be able to do it, actually do it on the court."
Compatriot Wawrinka and Gasquet qualified for London after Raonic, who only had a slim chance of snatching one of the last two spots, lost 7-6(13) 6-4 to Czech sixth seed Berdych.
Seventh seed Wawrinka, Djokovic's next opponent, beat Spaniard Nicolas Almagro 6-3 6-2 while Gasquet, who knew he had qualified for the London event before his match, breezed past Japan's Kei Nishikori by the same score.
Wawrinka is eighth in the ATP Race to London with Gasquet in ninth spot. The cut off point for qualification was lowered to ninth after British world number four Andy Murray pulled out of the season finale because of lower back surgery.
Third-seeded Spaniard Ferrer continued his bid to become the first man to retain the Bercy title by demolishing France's Gilles Simon 6-2 6-3. (Reporting by Julien Pretot; Editing by Martyn Herman and Ken Ferris)