MELBOURNE, Australia -- Serena Williams' superior athleticism again made the difference against Maria Sharapova.
After a neck-and-neck opening set, Williams ran away with a 6-4, 6-1 win Tuesday to advance to the Australian Open semifinals, the American's 18th straight win in the rivalry.
Despite the one-sided history, Sharapova matched Williams in intensity and velocity in the beginning.
In a titanic first set, No. 5 Sharapova broke Williams in the opening game and then held. The Russian stood firm on the baseline, taking balls early and keeping her opponent on her heels.