Test good for Williams

Serena Williams believes her Center Court scare against China's Zheng Jie was the perfect preparation for the sterner tests that lie ahead in the second week of Wimbledon.

The sixth-seeded American would have preferred a routine straight-sets win, but she is convinced the experience of coming back from the brink will make her even more battle-hardened in the remaining four matches that stand between her and a fifth Wimbledon title.

"It definitely helps me to realize that's it's not going to be easy going forward. I just have to stay focused," the former world No 1 said.