How exactly does it feel to hit a serve at 150 m.p.h.? Gerardo Valero, MEXICO CITY
It's better hitting it than having someone hit it against you. But I'll take a slow one that wins me the point as opposed to a faster one that doesn't.
You definitely had your chances of winning against Roger Federer at this year's Wimbledon final. What do you think are the things that cost you the match? Andrea Kim NORTHBROOK, ILL.
I don't think there are things. In the end, he put more returns on the court than I did in the fifth set.