Who can overthrow Serena Williams?

What happened to the Serena Williams conquerors? Here are a list of them...courtesy to ESPN.

Dinara Safina: She consistently came up short when she had the opportunity to consolidate her hold on the top spot or to make an authoritative statement validating the ranking.

Jelena Jankovic: She unfortunately overtrained at the end of last year, explaining her horrific start to 2009. It certainly doesn't explain her patchy, ragged, up-and-down year.

Svetlana Kuznetsova: Want to be No. 1, Sveta? "No, but thanks for asking!"

Elena Dementieva: It's funny how someone who seems like a no-nonsense player with great athletic gifts can find so many ways to avoid bagging a Grand Slam title or piecing together a run that takes her to the No. 1 ranking and keeps her there for good. My guess: She sabotages herself at some obscure emotional level.

Venus Williams: The demand of greatness is tough enough to begin with; it's that much more crushing a burden when your heart isn't exactly or entirely into it. (Just ask Andre Agassi.) Venus has become an error-prone and somewhat sloppy player, which tells you that she's mentally played out. And her problems were further exacerbated by the fact that her kid sister, Serena, simply appeared to want the top ranking more.

Vera Zvonareva: She's got an A-game but a C-spirit. She is famed for her emotional meltdowns on court.

Victoria Azarenka: She started strong but faded, consistently falling victim to her emotions. But unlike the self-pitying and easily broken down Zvonareva, Azarenka is a fighter who may learn to channel her anger and frustration in a positive manner. I'd watch out for her next year.

Maria Sharapova: She's recovering from a shoulder injury.

Ana Ivanovic: Please call home.

Caroline Wozniacki: Her game may not blow you away, with its moon-balling, retrieving defensive cast. But she's got a great attitude and took enormous strides in accepting her success with an impressive degree of composure and maturity. She shows signs of becoming a crafty, reliable and solid player who has what most of her peers lack -- the ability to find a way to win.