24 January 2013 Last updated at 15:32

Australian Open 2013: Victoria Azarenka defends timeout decision

Victoria Azarenka says she took a controversial timeout in her Australian Open semi-final win over Sloane Stephens because she "couldn't breathe."

The world number one left the court for almost 10 minutes because of breathing problems, with Stephens waiting to serve to stay in the match at 6-1 5-4 down.

Azarenka describes the incident as a "misunderstanding" and says the pain was "stressing" her out.