Affectionately called ‘Delpo’ by his fans, the 6 foot 6 inch Argentinian tennis playerJuan Martin del Potro is currently ranked number 5. Winner of the 2009 US Open and the bronze medal in the men’s singles at the 2012 London Olympics, he possesses what many consider to be the most powerful forehand in the game. A right-handed, two handed backhand player, he used the former to sign my sketch at the ATP World Tennis Finals at London’s O2.