Yes, he did.
Juan Martin Del Potro beat Roger Federer in the 2009 U.S. Open. I'm not sure if he beat him any other times though.
The final match was played between Roger Federer and Juan Martin del Potro. Juan Martin del Potro won the match. This was Juan Martin del Potro's first US Open Singles title.
The first semi final match was played between Roger Federer and Novak Djokovic. Roger Federer won the match. The second semi final match was played between Rafael Nadal and Juan Martin del Potro. Juan Martin del Potro won the match.
Juan Martin Del Potro defeated Roger Federer in five sets in '09
juan martin del potro and soderling
AO: Rafael Nadal d. Roger Federer FO: Roger Federer d. Robin Soderling W: Roger Federer d. Andy Roddick USO: Juan Martin del Potro d. Roger Federer
The first semi final match was played between Robin Soderling and Fernando Gonzalez. Robin Soderling won the match. The second semi final match was played between Juan Martin del Potro and Roger Federer. Roger Federer won the match
Federer has won only one French Open, in 2009.
No. Although Juan Martin Del Potro beat Federer and Nadal in the 2009 US Open and was the only one to do so in a Grand Slam, there have been other players to beat them both in a tournament, such as Murray at the 2010 Rogers Cup, and Djokovic at the Rogers Cup in 2007. See 'related links' for more information.
1: Roger Federer 2: used to be nadal now Novak Djokovic 3: Rafael Nadal 4: Andy Murray 5: Juan-Martin Del Potro 6: Andy Roddick 7: Nikolay Davydenko
Men- Juan Martin Del Potro defeated Roger Federer 3-6 7-6(5) 4-6 7-6(4) 6-2 despite winning only one more game than the Fed Express. Women- Kim Clijsters defeated Caroline Wozniacki 7-5 6-3.
Juan Martin Del Potro
2009 US Open Men's Final, Juan Martin Del Potro won against Federer in 5 sets, after 4 hours - YouTube.