Serena steps out on Centre Court today

Wimbledon champion Serena Williams will no doubt be looking for the support of big sister Venus when she steps out to start her title defence on Centre Court this afternoon.

Serena, aged 21, was off duty for eight months after winning Wimbledon last year and then had a left knee operation in August.

The knee was still an irritant as she suffered defeats to Nadia Petrova and Jennifer Capriati, the latter her earliest defeat in a Grand Slam – the French quarter-final – in three years.

Earlier this month Serena slipped out of the world’s top 10 for the first time since August, but because she is chasing a hat-trick at Wimbledon she is still number one here.

She faces an intriguing Chinese puzzle. Rival Jie Zheng, aged 20, became the first player from that country to reach the fourth round in a Grand Slam on the Roland Garros clay but played her first matches on grass only just a week ago in trying to qualify for Eastbourne.