If you're left-handed, currently in Paris and can break a nasty serve wide to the ad court, you might just be who Roger Federer is looking for.

Deep into the second week of Roland Garros, options for lefty practice partners are somewhat limited. But Federer is in need of lefty practice partners during the next two days as he prepares for his blockbuster Friday semi-final against arch rival Rafael Nadal.

Looking forward to their 39th FedEx ATP Head2Head meeting, Federer said that playing Nadal at Roland Garros was a massive challenge despite his own excellent form that he will take into the match.

“With Rafa, particularly on clay, you have to be aware of his strengths, what he brings to the table. And on top of it, because he's a left-hander, it just changes everything," Federer said.

“I have two days, which I guess is a good thing. It's better than one. It's better than none. So from that standpoint, I get more left-handed practice, more serves and all that stuff.

“Because I guess I have played five guys now that are righties, so for me it's a complete switch-around. Just the way the ball goes out of your strings with the different spins, it's just different. So you have to get used to that quickly. Don't have much time to waste.

“That's why 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."

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Nadal and Federer have met just once on clay in the past eight years: in 2013 in Rome. And they have not met on clay since Federer switched to a larger racquet head, which offers more protection against Nadal’s signature crosscourt forehand, which historically has haunted Federer on the dirt.

Although Federer is a modest 2-13 against Nadal on clay - including 0-5 at Roland Garros - the Swiss said that he believes he has a chance to advance to the final. On the upside, the Swiss is on a five-match winning streak against Nadal, the longest run in his favour in their rivalry, which Nadal leads 23-15.

“Like against any player, there is always a chance. Otherwise nobody will be in the stadium to watch because everybody already knows the result in advance,” Federer said. “And I think sport does that to you, that every match needs to be played before it's decided.

“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 never know. 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 gonna 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.”