Switzerland's Stan Wawrinka returns to Argentina's Juan Martin del Potro during their men's singles second-round match on the fifth day of the 2016 Wimbledon Championships at the All England Lawn Tennis Club in Wimbledon, England on Friday. The fourth seed was stunned 3-6, 6-3, 7-6 (7/2), 6-3 by the world No.165 Argentine. Photo: AFP