Serena Williams pulls out of next week`s Miami event

New York: World number one Serena Williams has pulled out of next week`s Sony Ericsson Open due to a knee injury, organisers said on Friday.

The American`s withdrawal is another blow to the tournament after former Wimbledon champion Maria Sharapova and world number two Dinara Safina had already pulled out. Williams has won the Key Biscayne event five times. Venus Williams and Svetlana Kuznetsova headline the women`s field while the men`s top three -- Roger Federer, Novak Djokovic and Rafa Nadal are joined by American Andy Roddick and defending champion Andy Murray.Bureau Report