Re: Kim Clijsters says Serena Williams was her toughest opponent of her career
H2H really doesn't mean anything.
After 2003, Clijsters won 6 matches out of 7 against the Williams sisters, but only one match-up with Serena. I'm not saying she was the overwhelming winner after 2003 once she played one of the sisters. But she obviously could have a better H2H against Serena if she had more chances of playing Serena.
I think it's prolly because she lost to Serena too many times before she gained the confidence on Tour and matured her game. I bet she was completely beaten mentally after that slump in Australia in 2003. Just like Justine admitted that she was still fearful of playing Venus in 2007 altho she later on proved that she could totally compete with Venus at that time.