Here is something I did not know: Caroline Wozniacki, who recently made the final round of the US Open before falling to a comebacking Kim Clijsters (7-5, 6-3), boxes with Mikkel Kessler's trainer as part of her workouts:

Wozniacki is a delightful personality. She has played more matches this year (80) and won more (62) than any other woman, and is complete in all phases of the game. But while Clijsters is a knockout artist, Wozniacki is strictly a counterpuncher.

After losing in the fourth round at Wimbledon, she followed some advice from her friend Mikkel Kessler, the current WBA super middleweight champion, and began working with trainer Poul Duville. Wozniacki followed the boxer's regimen of working the treadmill and throwing a passel of punches -- first to Duville's big soft catching mitts, later to his midsection as they sparred.

"I've become faster, more lean, stronger," Wozniacki said at the New Haven tournament. "That really helps my game, because in pressure situations out on the court, I still am able to hit the ball back strongly."

I'm a huge Kim Clijsters fan -- but this makes me like Wozniacki a lot more as well.