 Juan Martin del Potro and Roger Federer have played 20 times with Federer leading 15 – 5 . They have met six times in Grand Slam tournaments with Federer leading 5 – 1 . Their two most famous Grand Slam tournament meetings both came in 2009 . The first was in the French Open semifinals , when Federer survived an epic five @-@ set clash when he was chasing the only French title of his career . The second was in the final of the US Open , where del Potro stunned Federer in five sets , ending his 20 @-@ match winning streak at majors . Another high @-@ profile match was in the semifinals of the 2012 London Olympics , where Federer prevailed 19 – 17 in a <unk> final set to secure the Olympic silver medal . Most recently , they met in the finals of the Swiss Indoors in 2012 and 2013 , with del Potro prevailing on both occasions in tight three @-@ set matches . 
