Roger Federer does not believe there is anyone who can help him prepare for Rafael Nadal on clay after the reigning French Open champion was the dominant winner in their semi-final on Friday.

Nadal reached his 12th final at Roland Garros by recording his sixth victory in as many matches against Federer in Paris, surging to a commanding 6-3 6-4 6-2 triumph on Court Philippe-Chatrier in two hours and 25 minutes.

The 20-time major champion boasts just two wins in 16 meetings with the 'King of Clay' on the red dirt, his only successes coming in Hamburg in 2007 and in Madrid two years later.

Federer was making his first appearance at Roland Garros since 2015, missing 2016 with injury and the 2017 and 2018 tournaments to focus on grass and hard courts, and is unsure any training partner could improve his chances against the Spaniard.

"He makes you feel uncomfortable the way he defends the court and plays on clay. There is nobody who even plays remotely close to him," said the Swiss.

"I don't even know who I need to go search for to go practice with somebody who plays like him. I was thinking that during the match.

"It's just amazing how he plays from deep and then is able to bounce back and forth from the baseline. It's just quite interesting.

"But my mindset still was, it's windy, anything can happen. I didn't play poor [in the] two first sets in my opinion.

"I thought Rafa really had to come up with the goods to make the difference, and the difference was a passing shot here, a pick up there, and then he was doing great."

Federer was pleased by his performances at Roland Garros after three years off clay and suggested it makes it more likely he will return next year.

"I think I played really well. I think I surprised myself maybe how deep I got in this tournament and how well I actually was able to play throughout," he said.

"And next year, just like with any other tournament, I don't know. We'll see what happens. But I definitely enjoyed the clay-court season and the French Open, so that would help the chances to return to the clay.

"It's not like it's been a shocker. So from that standpoint, it's okay."

On the exceptionally windy conditions on Chatrier, he added: "You get to a point where you're just happy to make shots and not look ridiculous. It's that bad. It's just really difficult for both of us.

"I don't think I played poorly in the wind today. It's just it's tough on clay. You've got to try to take on the half-volleys, too, all that stuff. It just adds to the equation. He's the best clay-court player, so I can accept that. It's not a problem."