1 July 2014 Last updated at 18:02

Wimbledon 2014: Serena Williams struggles to serve through illness

Serena Williams is forced to retire from the doubles event after suffering from a viral illness during her match with sister Venus against Stefanie Voegele and Kristina Barrois.

Williams needed lengthy treatment from the doctor and trainer for dizziness after the warm-up, and retired after serving four double faults in her first service game.

Available to UK users only.