Spanish tennis player Feliciano Lopez in action against German Benjamin Becker during their Madrid Open tennis tournament first round match played at Caja Magica sports pavilion in Madrid, Spain, 04 May 2015. EPA/JUANJO MARTIN

US tennis player Serena Williams returns the ball to her countryman Madison Brengle during the second jouney of the Madrid Mutua Open tennis tournament match at the Caja Magica pavilion in Madrid, Spain, 03 May 2015. The Madrid Mutua Open runs from 01 to 10 May 2015. EPA/JUANJO MARTIN

Russian tennis player Maria Sharapova returns the ball to Swiss Timea Bacsinsky during the second round of the Madrid Mutua Open tennis tournament at the Caja Magica pavilion in Madrid, Spain, 03 May 2015. The Madrid Mutua Open runs from 01 to 10 May 2015. EPA/CHEMA MOYA

Andy Murray of Scotland returns to Philipp Kohlschreiber of Germany during the ATP finale in Munich, Germany, 04 May 2015. The ATP finale between Murray and Kohlschreiber had to be interrupted due to rain on 03 May and was continued on 04 May.  EPA/MARC MUELLER

Andy Murray of Britain celebrates after winning the final match against Philipp Kohlschreiber of Germany at the ATP tennis tournament in Munich, Germany, 04 May 2015. EPA/MARC MUELLER