The Spaniard adapted superbly to the swirling wind inside Philippe-Chatrier as he won 6-3 6-4 6-2. He will face either Novak Djokovic or Dominic Thiem in Sunday’s final.
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It was a gloomy end to an otherwise brilliant tournament for Federer, who was making his return to Roland Garros for the first time since 2015.
"It's incredible, congratulations to Roger," Nadal said on court afterwards. "It's incredible to play at that level aged 37.
"He's probably the best player in history, it's a great pleasure to play with him. Tough conditions with a lot of wind, I'm very happy to be back in the final at Roland Garros which is the most important tournament in my career."
Federer's hopes of winning a second title in Paris – and a first win over Nadal in his backyard – were dashed by his inability to consolidate breaks, with Nadal hitting back immediately on both occasions he managed to breach his old foe’s serve.
Victory extended Nadal’s dominance in their head-to-head to 24-15 and boosted his record at Roland Garros to a ridiculous 92-2. Should he win Sunday’s showpiece, he would slice Federer’s lead in the Grand Slam charts to just two – 20 would play 18.
Nadal has dropped just one set all tournament, against David Goffin in the third round, with the 33-year-old again demonstrating why he is the greatest clay-court player in history.
His ability to neutralise Federer’s serve was crucial to his success, while he produced a series of unplayable passing shots to bypass his net-rushing opponent.
The biggest obstacle to Nadal's charge were the conditions as strong winds moved the ball around mid-flight and flung up red dust off the court surface, leaving the arena often resembling a sandstorm. But he dealt with it supremely and, on this evidence, nothing will stop him winning another title in Paris.
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