Juan Martin Del Potro of Argentina returns to Lucas Pouille of France during their third round match at the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2016 EPA/FACUNDO ARRIZABALAGA

Sloane Stephens of the US returns to Svetlana Kuznetsova of Russia in their third round match during the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2016. EPA/GERRY PENNY

Alexander Zverev of Germany returns to Tomas Berdych of Czech Republic during their third match at the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2016 EPA/ANDY RAIN

Feliciano Lopez of Spain returns to Nick Kyrgios of Australia in their third round match during the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2016. EPA/GERRY PENNY

Annika Beck of Germany serves to Serena Williams of the USA during their third round match at the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2016 EPA/ANDY RAIN