Barclays ATP World Tour Finals - Previews [Getty Images]

LONDON, ENGLAND - NOVEMBER 07: L-R Stan Wawrinka of Switzerland,Milos Raonic of Canada,Tomas Berdych of Czech Republic,Novak Djokovic of Serbia,Kei Nishikori of Japan,Andy Murray of Great Britain,Roger Federer of Switzerland and Marin Cilic of Croatia all pose for the mens singles official group shot prior to the start of the Barclays ATP World Tour Finals tennis previews at the O2 Arena on November 7, 2014 in London, England. (Photo by Clive Brunskill/Getty Images)

Getty Images Sport Clive Brunskill