* Ferrer could be first to win back-to-back titles
* Djokovic exhausts Federer (Add quotes, details)
By Gregory Blachier
PARIS, Nov 2 (Reuters) - Spaniard David Ferrer produced one of his finest performances to edge world number one and compatriot Rafael Nadal 6-3 7-5 in the Paris Masters semi-final on Saturday and keep alive his hopes of being the first player to retain the crown.
Third seed Ferrer, who won his first Masters Series title in Paris last year, will face Novak Djokovic in the final of the indoor event on Sunday after the Serb earlier subdued Roger Federer 4-6 6-3 6-2 in a battle of former world number ones.
Ferrer could be the first player to win back-to-back titles at the indoor event if he beats Djokovic, who needs to win the tournament to entertain his slim chance to reclaim the ATP top spot by the end of the year.
Ferrer, who entered his match with a 4-20 win-loss record against Nadal but had won their previous encounter on hard courts, at the 2011 Australian Open, dominated from the first point to the last.
He began aggressively, forcing Nadal to defend and breaking his opponent's serve in the fourth game.
Nadal regrouped and created three break chances in the second game of the second set, only to see Ferrer level at 1-1 and then take advantage of one of the top seed's numerous errors to lead 2-1.
Nadal threatened to record a great comeback when he levelled at 5-5, but Ferrer broke immediately and wrapped up the match on his first chance with a powerful groundstroke.
"It was a very good match for me. I played maybe my best match this season, very aggressive with my forehand and with my shots," Ferrer told a news conference.
"I know when I play with Rafa I have to play my best tennis. And him, he hasn't to play his best tennis too, sure. I think this week I have been playing very good ... with real power with my forehand and maybe the key was my serve.
"Today, I played a very complete match."
IBRAHIMOVIC ON COURT
Nadal said he was not at the level required to beat Ferrer.
"I need to move quicker. I was slow. I felt like I did not move - I always was a little bit late on the ball," he said.
"Against a player like David, who's quick and plays inside the court and puts pressure on you all the time, you are dead. It was like this."
With Paris St Germain striker Zlatan Ibrahimovic watching, power had also made the difference earlier on Saturday as 2009 champion Djokovic defeated Federer despite struggling to control the brilliant Swiss early on.
"The key was just to hang in there and stay with him. I knew that he was going to be very aggressive from the start coming to the net. He used his opportunities really well," Djokovic said.
"Then, you know, I tried to decrease the number of unforced errors and step in when needed. I did pretty well in the second and the third."
While the crowd had loudly supported Federer throughout, Djokovic earned his share of applause when he invited his friend Ibrahimovic to hit a couple of balls with him after match point.
It had not been that easy from the start as Federer, who has slipped to sixth in the rankings after enduring his worst season in 10 years, broke his opponent's serve in the third game.
The 17-times grand slam champion unsettled Djokovic by attacking the net as often as possible and hitting some sharp groundstrokes.
Federer looked set to qualify for his first Masters Series final this year when he broke Djokovic again in the opening game of the second set, but the Serb hit back for 1-1.
Federer lost the initiative after errors began to creep into his game and he also struggled with his serve. Djokovic broke Federer's serve a second time to lead 4-2 and he carried the momentum through the deciding set.
Both players will meet again next week at the ATP World Tour Finals in London after they were drawn on Saturday in the same round-robin group.
(Editing by Pritha Sarkar/Stephen Wood/Rex Gowar)