Croatia’s Franco Skugor returns the ball to Spain’s Inigo Cervantes during their first round match of the 64th Barcelona Open Banc Sabadell Conde de Godo tennis tournament in Barcelona, northeastern Spain, 18 April 2016. EPA/ALEJANDRO GARCIA

Richel Hogenkamp of the Netherlands in action against Kristina Mladenovic of France during the Fed Cup Tennis World Group semi-final tie between France and the Netherlands at Loire Arena in Trelaze, France, 16 April 2016. EPA/EDDY LEMAISTRE

Spanish tennis player Roberto Bautista returns the ball to Russian Karen Khachanov during their Barcelona Open Banc Sabadell Conde de Godo Trophy first round match in Barcelona, northeastern Spain, 19 April 2016. The tournament runs in Barcelona from 18 until 24 April 2016. EPA/Alejandro Garcia

Daria Gavrilova of Australia in action against Madison Keys of the US during their match of the 2016 Fed Cup tennis tournament World Group playoff between Australia and the United States at Pat Rafter Arena in Brisbane, Australia, 16 April 2016. EPA/DAVID KAPERNICK

Rafael Nadal of Spain returns the ball to Andy Murray of Great Britain during their semi final match at the Monte-Carlo Rolex Masters tournament in Roquebrune Cap Martin, France, 16 April 2016. EPA/SEBASTIEN NOGIER