Britain’s Laura Robson is making changes in her service motion under new coach Miles Maclagan. The British teenager — who drew 10th seed Maria Kirilenko in the first round of Wimbledon — has  hit 94 aces and 162 double faults in 2013.

British TV analyst Sam Smith told the BBC that the left-handed Robson’s serve will develop into  “one of the best serves in women's tennis very, very soon."

Notable coach Nick Bollettieri added: "Her biggest asset is being a lefty. She's improving that wide, slice serve, which is very, very important as, normally speaking, it will go to a righty's backhand, but you have to be very, very careful even making a small adjustment. Making a change at 19, you have to hold your breath somewhat. You don't want to tinker with lefties too much because they have a more natural slice than a righty."