Updated On: 09 July, 2015 08:32 AM IST | | PA Sport
<p>On the eve of her semi-final clash against Sharapova, World No 1 indicates she saves her best performances for clashes with her fiercest rival<br /><br /></p>

World No 1 tennis ace Serena Williams reacts during her quarter-final match against Victoria Azarenka at Wimbledon on Tuesday
London: Serena Williams has flexed her Wimbledon authority by firing an early mind-games salvo ahead of her grudge semi-final with Maria Sharapova.

World No 1 tennis ace Serena Williams reacts during her quarter-final match against Victoria Azarenka at Wimbledon on Tuesday. Pics/AFP