Great Britain's Andy Murray with his coach Ivan Lendl in a practice session during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

France's Kenny Schepper in action against Spain's David Ferrer

Russia's Maria Sharapova in action against Bulgaria's Tsvetana Pironkova

Great Britain's James Ward in action against USA's Mardy Fish during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Great Britain's James Ward celebrates winning a set in his match against USA's Mardy Fish during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Japan's Go Soeda in action against Argentina's Juan Martin Del Potro

Great Britain's James Ward during a break against USA's Mardy Fish

Czech Republic's Lukas Rosel celebrates beating Spain's Rafael Nadal on day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Umpires in their chairs during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Spain's David Ferrer in action against France's Kenny Schepper

Russia's Maria Sharapova in action against Bulgaria's Tsvetana Pironkova

Great Britain's Andy Murray in action against Croatia's Ivo Karlovic on day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Great Britain's Andy Murray celebrates defeating Croatia's Ivo Karlovic during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Great Britain's James Ward reacts during his match against USA's Mardy Fish during day four of the 2012 Wimbledon Championships at the All England Lawn Tennis Club, Wimbledon.

Canada's Milos Raonic in action against USA's Sam Querrey

Great Britain's Andy Murray