Roger Federer "very happy" to be facing old rival Rafael Nadal at French Open

Roger Federer vowed to be "fearless" when he takes on his old rival Rafael Nadal for the 39th time in the French Open semi-finals on Friday.

Having returned to the tournament after a four-year hiatus, Federer has produced some vintage form on the clay and he was superb in a 7-6 (4) 4-6 7-5 (5) 6-4 victory over fellow countryman Stan Wawrinka to make the last four for the first time in seven years.

Nadal leads his head-to-head against Federer 23-15 and has won all five of their matches at Roland Garros, most recently in four sets in the final in 2011.

It is fully 10 years since Federer last beat Nadal on clay, in the final of the Madrid Open, but he has won their last five matches.

"Against any player, there is always a chance," he said. "And that's exactly what everybody believes by facing Rafa. They know it's going to be tough. But you just never know.

"He might have a problem. He might be sick. You might be playing great or for some reason he's struggling. Maybe there's incredible wind, rain, 10 rain delays. You just don't know. That's why you need to put yourself in that position.

"For me to get to Rafa is not simple. It took five matches here for me to win to get there. That's why I'm very happy to play Rafa, because if you want to do or achieve something on the clay, inevitably, at some stage, you will go through Rafa, because he's that strong and he will be there.

"I knew that when I signed up for the clay that hopefully that's going to happen. If I would have had a different mindset to avoid him, then I should not have played the clay. So I think by that mindset, I think it helped me to play so well so far this tournament.

"You have to be fearless to some extent to take on the spinny balls, the sliding balls, the kicking balls, and that's what I will do on Friday."

Wawrinka had beaten Federer in straight sets in the quarter-finals here four years ago, going on to win the title.

The crunch moments of this all-Swiss contest came in a third set that both men might have won but ultimately it was Federer who was just the stronger.

Nevertheless, this has been the tournament where Wawrinka positioned himself back at the top of the game, particularly in a five-hour marathon against Stefanos Tsitsipas in the fourth round.

"Today I was playing great," said Wawrinka. "He was playing the way I expect him to play against me and on a clay court.

"There is no surprise any more in what we are doing. It's just about who's going to play the best in those important points, and he did that better than me. He was a bit more aggressive in the right moment."

Nadal's match was much more comfortable, the second seed easing into a 12th semi-final here with a brutal 6-1 6-1 6-3 victory over seventh seed Kei Nishikori.

Nishikori had been pushed to five sets in his previous two matches and could find nothing to hurt Nadal, who will now look to maintain his record of never having lost at Roland Garros once he has reached the last four.

The only thing that held him up was a brief thunderstorm in the third set. Nadal looked decidedly unhappy to be instructed to leave the court at 4-2 but wasted little time wrapping things up on the resumption.

Nadal said of facing Federer again: "For me, the main thing is being in the semi-final. The way that I have been playing has been very positive.

"Of course having Roger in front in the semi-finals is an extra thing. We shared the most important moments of our careers together on court facing each other.

"So it's another episode of this, and I'm happy for that and excited. It will be a special moment, and let's try to be ready for it."