Grigor Dimitrov of Bulgaria serves to Jerzy Janowicz of Poland during the second round of the Western and Southern tennis tournament at the Lindner Tennis Center in Mason, Ohio, USA, 13 August 2014. EPA/MARK LYONS

Grigor Dimitrov of Bulgaria serves to Ivo Karlovic of Croatia during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 27 May 2014. EPA/YOAN VALAT

Grigor Dimitrov of Bulgaria celebrate shis win over Kevin Anderson of South Africa in their quarter-finals match of the Rogers Cup mens tennis tournament in Toronto, Canada, 08 August 2014. EPA/WARREN TODA

Bulgarian tennis player Grigor Dimitrov returns the ball to Spain’s Rafael Nadal during their semi-final match for the Italian Open tennis tournament at the Foro Italico in Rome, Italy, 17 May 2014. EPA/ETTORE FERRARI

Grigor Dimitrov of Bulgaria hits a return to David Goffin of Belgium during the seventh day of the 2014 US Open Tennis Championship at the USTA National Tennis Center in Flushing Meadows, New York, USA, 31 August 2014. The US Open runs through 08 September, a 15-day schedule. EPA/JUSTIN LANE

Bulgarian Grigor Dimitrov returns against Cypriot Marcos Baghdatis during their match of the Acapulco Tennis Open in Acapulco, Mexico, 26 February 2014. EPA/Jose Mendez