Yet, if we return to Mary Carillo’s point from two weeks ago -- that the Williams sisters haven’t lived to their potential -- here’s something that underscores it.

Serena Williams has finished only one year at number one; Venus Williams never has.

Here’s a look at the number of weeks some big names have spent at number one: 

No one's going to argue with their amazing record in the big tournaments. But just think how dominant they'd be if they played all the time.