Swiss tennis player Roger Federer smiles during a press conference... Nieuwsfoto'sArgentinië,Buenos Aires,Eén persoon,Glimlachen,Horizontaal,Juan Martin Del Potro,Mensen,Persconferentie,Roger Federer,Sport,Tennis,Tentoonstelling,Vlak naast,Zwitserse cultuurPhotographer Collection: AFP 2012 AFPSwiss tennis player Roger Federer(R) smiles during a press conference with Argentinian Juan Martin Del Potro (not in picture), in Tigre, near Buenos Aires, on December 11, 2012, ahead two exhibition matchs that will be held on 12 and 13 December. AFP PHOTO / Alejandro PAGNI (Photo credit should read ALEJANDRO PAGNI/AFP/Getty Images)