Wimbledon 2014: Williams looks drained - Tracy Austin

Former Wimbledon mixed doubles champion Tracy Austin joins Sue Barker to react to the news that Serena Williams has suffered her earliest defeat in the Championships since 2005.

Austin believes fatigue is an issue and says the the five-time Wimbledon champion looks "drained" and "tired."

The American went on to praise Williams' opponent Alize Cornet, who has never beaten a top-20 player at a Grand Slam.