THREE DARK HORSES

The 2014 US Open champion has a booming serve. Now the Croat has added more mobility and improved volleying after working with Andy Murray’s former coach Jonas Bjorkman. Reached final at Queen’s.

Best known for his celebrity girlfriends (Serena Williams, Maria Sharapova and now Nicole Scherzinger) the former junior world No.1 is coached by Andy Murray’s former coach Dani Vallverdu. The 2009 US Open champ’s career has been dogged by wrist injuries but he has form on grass. Reached the Olympic semis here in 2012 – and the Wimbledon last-four the following year.