"Like Federer...Without a Nadal"

It's not often that I agree with Mary Carillo. But during today's women's title match between defending champion Serena Williams and first-time finalist Vera Zvonareva, she came up with a very appropriate analogy, comparing Serena's dominance in tennis to Roger Federer's, if there were no Rafael Nadal. Not to belittle Fed's accomplishments by any means, but just think of how many more Majors he'd have won if Nadal hadn't been in the way -- since 2005 Roger has lost five times in the finals to the Spaniard and one more time in the semis.

That realization got me thinking if there really is anyone out there who can challenge Serena's spot at the top. In her thirteen Slam championships, she has never had a foil quite like Nadal. Sure, older sister Venus can sometimes get under her skin, but in the past five years, she's only lost one Major title at the hands of Venus. And there are players who can have moments of brilliance against her -- Jelena Jankovic, Nadia Petrova and Sam Stosur have all outlasted her in recent three-set matches. It's hard to be consistently on top of Williams -- the way she served at the All England Club, opponents rarely got a shot to break. And when she's healthy and focused, her shots always seem to find their mark.

But there are a couple players out there who've had a bit more luck.

In her first career Kim Clijsters surprisingly only got the better of Williams once, at the Tour Championships in 2002. They didn't meet in more than six years before that fateful U.S. Open semi last year, but from what I saw of the Belgian, she'd certainly figured something out in the interim. If they play again, which I'm sure they will during the upcoming hardcourt season, Kim might be able to improve her win percentage.

Countrywoman Justine Henin had a bit better luck against Serena before she retired, beating her four times at a Major and another two when a title was on the line. Despite her diminutive frame and lackluster serve, she kept things fairly level throughout their history, even taking a set from her at the Australian Open this year.

Then there's Elena Dementieva, the only woman other than her sister to take a set from Williams at Wimbledon in the last three years. The Russian actually has a stunning 5-3 record over Serena in the last five years, beating her once on the way to Olympic Gold and twice when another championship was on the line, and she's done so decisively -- her last three wins have been in straight sets. There is some cause for concern, though, as a calf injury forced her to withdraw from the Championships this year and ended her streak of forty-six straight Grand Slam appearances.

But though these ladies might all know what it takes to beat Serena time and time again, the problem is that they can be much less consistent against other players, which makes their chances of reaching the round in which they face the world #1 a lot slimmer. So for the time being, as if we didn't know, it's going to take a lot to dethrone the current queen. And until a solid "Nadal" presents herself, it might be a while before anyone gets a crack at the top.