Yeah well - you have your bad days and your good days.
The fact remains that:
a. Mary has been a world-class player
b. She still hits the ball better than 99% of the tour - is up there with Williams, Capriati, Davenport
All Mary needs to do is get much, much faster on her feet and I hope this fall she attempts to seriously work on this. If she does that her results will surely improve!