Defeated the Swiss 7-6 (6), 6-2, 6-4 Gael Monfils at the French and reached the semifinals of a major for the 20th consecutive time. Del Potro, however, advanced to his first semifinal of a Grand Slam to win 6-3, 6-4, 6-2 to Spanish Tommy Robredo.
Del Potro is the first semifinalist at Roland Garros since Argentine David Nalbandian lost to Federer in 2006. His best result so far in a major was the quarterfinals of the United States Open in 2008 and the Australia Open in 2009.
I'm very happy, I'm in a semifinal of a Grand Slam, said Del Potro. This was a very difficult match for both, we knew we had opportunities. The most important thing was to win and play with Federer on Friday.
Pre fifth has never won in five encounters with the Swiss in the second world ranking, although experiencing a great moment after a roll Robredo and French Jo-Wilfried Tsonga in the final round.
The native of Tandil, in 20 years, even won a set against Federer in their grief, which is crowned by road for the first time in the brick dust of Paris.
He (Federer) does everything with his perfect game. His game gives me many problems, and so I've never won, said Del Potro. We have played many games, so we already know. I think I know what's going to do, and I will do my utmost to return his serve and by doing so they, not give any points.
Federer lost the last three finals in Roland Garros at the hands of Rafael Nadal, but no longer have to worry about the Spanish that was eliminated in round, Robin Soderling.
It will be a good match. I took the advantage at the moment. Already we have faced and I have several victories advantage, Federer said about his duel with Del Potro, who won this year in the semifinals of the Madrid Masters.
In Madrid, the event on clay was much more closed. It is true that in recent years has greatly improved. Will then be a very difficult, he added.
Soderling will dispute the other semi final against Chilean Fernando Gonzalez, whose 4-3 mark against the Swedish.
Federer seeks his 14th Grand Slam title, which empataría record with Pete Sampras.
I felt some pressure before the match against Monfils, Federer confessed. I was very nervous because I thought it would be very difficult.
For its part, Serena Williams was eliminated by Svetlana Kuznetsova in the quarterfinals of the women's arm and lost the chance to win his third consecutive title in a Grand Slam tournament.
The U.S. did not take one set point in the first set and eventually fell 7-6 (3), 5-7, 7-5 before the Russian.
Kuznetsova saved a break point when they drew 5-6 in the first set. After winning nine of the next 10 points to take advantage.
Williams won the last three points in the second set and took advantage of 3-1 in the third. But Kuznetsova broke back and the service in the last game.
In the third set I had an opportunity and I became very nervous, and basically gave him, said Williams. It was like saying, take, want to go to the semifinals? Because I do not want.
Honestly, I think I lost my fault and not something she has done, he added.
The U.S. Pre second, he had won 18 matches in a row in the majors and was looking for his 11th Grand Slam title.
Kuznetsova will face in the semifinals of the Australian Samantha Stosur, who crushed 6-1, 6-3 to Romanian Sorana Cirstea.
Stosur broke him twice to take his opponent in the first set and three times in the second, including the last game.