Djokovic hammered France´s Richard Gasquet 6-1, 6-2 as the top seed motored into final four. Nadal was equally ruthless with Australian qualifier Marinko Matosevic 6-4, 6-2.
Nadal leads his Serbian rival 20-15 in their career series with the pair having played twice in 2013. Nadal beat Djokovic in a five-set thriller in the semi-finals of the French Open, just weeks after the world number one had taken the Spaniard´s Monte Carlo crown in the final.
Milos Raonic and wildcard Vasek Pospisil set up an all-Canadian semi at the bottom of the draw.
Pospisil, living the dream week of his career, had it easy in his quarter-final as Russian opponent Nikolay Davydenko retired with a respiratory ailment while trailing 3-0. Raonic, overcame Latvia´s Ernests Gulbis 7-6 (7/3), 4-6, 6-4.
Pospisil had reached the quarter-finals with his first top-10 victory, a third-round defeat of Tomas Berdych.
Djokovic, a three-time champion in Canada who is bidding for his third-straight title at the event, won his eighth match out of nine against Gasquet and his sixth in a row in the series.
"Everything was working in my game," said the winner, "It was close to the perfection. In every part of my game I did almost my best.
"From the start I tried to dictate the play on the court and be in control of the rallies. I´ve done really well. The serve was very efficient, very high percentage of first serves, a lot of aces, a lot of free points.
"That´s something that obviously gives you confidence when you´re playing at this level."
Nadal, leading the ATP on seven titles this season, spent an hour and a quarter in dispatching Matosevic. He said that after a seven-week pause following an early Wimbledon loss that his problem left knee feels fine.
"I´m happy with the way that it feels and also with having a chance to play after such a long pause. To be in a semi-final on fast hardcourt now is amazing for me. I´m enjoying every moment.
"I need to try my best and play my best tennis if I´m to have a chance against Novak. The court is fast and that will favor him, but I´m glad to be in the semi-finals."
Raonic and Pospisil are the first Canadians since Mike Belkin in 1969 to reach the semi-finals of this event.
Raonic, starting to thrive under the guidance of new coach Ivan Ljubicic, ran his record over Gulbis, conqueror of Wimbledon champion Andy Murray 24 hours earlier, to 4-0.
Pospisil is trying to keep a grip on his emotions.
"This is a huge week for me (ranking) points-wise. Top 50 was a life-long goal of mine, the goal that I set at the beginning of this year. Now I´m there already.
"So my goals are already changing. I´ll try to reset them a little bit and try to keep moving up."
World number 13 Raonic has come out of a trough this week after failing to get past the third round during the past three months.
Raonic is looking forward to the unprecedented clash.
"It´s great in what it represents for Canadian tennis," said Raonic. "It´s great what it shows to little kids: that you can succeed as a Canadian in tennis.
"But for what I want to achieve, what I´ve got to do to prepare myself as best as possible for tomorrow, it doesn´t change anything."
Serena downs Radwanska, books final with Cirstea
TORONTO, Canada / Province of Ontario, Aug 11: World number one Serena Williams defeated Agnieszka Radwanska 7-6 (7/3), 6-4 on Saturday to reach the WTA Toronto final, where she´ll face giant-killer Sorana Cirstea.
Williams maintained her perfect record over Radwanska, her six wins over the world number four from Poland including a triumph in the 2012 Wimbledon final and, more recently, in the semi-finals at Miami this year.
Williams next faces unseeded Romanian Cirstea, who toppled fourth-seeded Li Na of China 6-1, 7-6 (7/5).
The victory over 2011 French Open champion Li continued a dream run for 27th-ranked Cirstea in the $2.4 million hardcourt tournament.
She also beat former world number ones Caroline Wozniacki and Jelena Jankovic, as well as defending champion Petra Kvitova, en route to the final.
"Gosh, she hits really hard," Williams said of Cirstea. "She has a really big serve. She moves well, she´s definitely not an easy player to play.
"She is a player who has finally found herself, and she´s playing better and better and getting more confident."
Williams found herself in a tight battle against Radwanska, twice recovering a break in the opening set before holding to force the tiebreaker.
She took control early in the tiebreaker, taking a 3-1 lead, and gave herself a triple set point with a cross-court winner for 6-3.
She needed just one of those set points, firing an ace to seal the set.
"This is what makes her number one in the world, playing unbelievable in very important moments and just very powerful shots," Radwanska said.
But Williams was clearly frustrated as she again went down a break to trail 3-1 in the second.
"I don´t think I was playing as aggressive as I needed to play," Williams said. "I let her play her game, which is what she wanted to do, but I wasn´t able to play my game as much."
Once again, however, Williams rallied. After a medical timeout because of a stomach ailment, she regained the break to level the set at 3-3 with a fierce overhead winner to end a long rally on her third break chance.
Williams then saved a break point to hold for a 5-4 lead, and broke Radwanska in the last game with a backhand winner followed by a high forehand volley on match point to seal the victory in one hour and 51 minutes.
"So, well, next time," Radwanska said.
Cirstea was looking forward to her shot at Williams.
"I am really excited for what´s happened this week and for tomorrow," she said. "Everything now is coming together for me."
The 23-year-old Cirstea cruised through the first set before Li jumped out to a 4-1 lead in the second.
Cirstea won five of the next seven games. She was unable to convert two match points in the 12th game as Li forced the tiebreaker.
In the decider, Li again gained the advantage, but Cirstea won six of the last seven points and clinched the semi-final victory on her third match point when a mistake-prone Li double-faulted.
"I´m happy with how I fought in the end and I´m really happy to finish the match in two sets," said Cirstea, who won her lone singles title five years ago at Tashkent.
Li, playing her first tournament since a quarter-final exit at Wimbledon, said she will just have to regroup for the next tournament.
"When I lose a match I am always a little bit sad," Li said. "But still have to find some positives.
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