I've said it before and I'll say it again: the Williams sisters just don't bring the same intensity to what they see as 'warm-up' tournaments. The WTA Tour can try all they like to make Cincinnati a big event, but to Venus and Serena a warm-up for the US Open is all it'll ever be.
The other leading women players might not feel that way, but they also lack the consistency that the best men do - and they are all there to be shot at by almost anybody out there.
It's odd that it's this way round these days. In the past it was always the top women who were unbeatable, while the leading men regularly would go down to lower ranked opponents. Any player in the top 100 always felt like they might be able to take Sampras down, for example, if he had an off day with his serve timing.
Today, the top guys are just so good, so tough to beat, so fit and so consistent that even if they have an off day they seem to just come through. You look at the likes of Roger Federer and Andy Murray and know that there's really nobody outside the top half dozen in the world who goes on court thinking they have a chance of winning.
Federer especially has got that aura of invincibility back. He lost it for a long time, through a combination of his illness and perhaps a few wobbles in his own confidence against players like Nadal and Murray - but he's truly earned it back now.
There's nobody in the women's game even close to that level. Serena Williams might not have been feeling well on Thursday night, but to me it looked more like she was mis-timing the ball in appallingly hot, humid conditions than anything else.
If it had been a Grand Slam, you just feel that she'd have found what she needed to get through the match. But it wasn't - and Flavia Pennetta has picked up yet another big scalp without having to produce much of a performance.
Pennetta's an interesting player; in my eyes she's always had the game to be a top five, but has never managed to string together the consistent results needed to achieve that.
However, at this precise moment in time she's playing the best tennis in the world and has to be considered a good outside bet to win the US Open.
But the women's game is wide open, with stars who seem to be misfiring all too regularly.
Which makes it all the better than Kim Clijsters's comeback is proving to be every bit as exciting and outlandish as we'd all hope it would be.
Clijsters has already shown that she's lost none of her fitness and intensity, and although there are a few too many moving parts in her game at the moment, I wouldn't put anything past her. And I include winning another US Open title.
Above all, the women's Tour must be relieved beyond belief that she's come back. She's once again made women's tennis a fascinating spectacle, just when it looked to be struggling.
- Serena Williams
- Andy Murray
- Roger Federer