Former world No. 1 and seven-time Grand Slam champion Mats Wilander is writing exclusively for Yahoo! Sports throughout the U.S. Open. The 1988 U.S. Open champ breaks down who's hot and who's not, offering his thoughts courtesy of Lacoste.
Kim Clijsters has been the perfect story at this U.S. Open - now she needs to play the perfect match to have any chance to further progress.
Clijsters has done brilliantly to make the semifinal in her first Grand Slam since returning to tennis after becoming a mother and taking two years out.
But next she takes on Serena Williams for a place in the final and that contest will be an entirely different prospect to anything she has faced so far.
The Belgian has a reasonable game to cope with Serena's power, because she is strong and flexible enough to stay in long rallies and is not afraid to go on the defensive to stay in points instead of going for a low percentage winner.
She must try to control the match with her forehand yet the big challenge will be to handle the extra power Serena brings. To do that, Clijsters' timing must be perfect.
Realistically, it is hard to see Clijsters causing an upset, but one thing that will actually work in her favor is that she has not been around the locker room recently.
Seeing Serena struggle so badly in smaller tournaments, then turn into this awesome player in the majors is disconcerting for the other players and hard to adapt to mentally.
That will be a boost to Clijsters, yet I still don't think it will be nearly enough. Serena's serve will be just one crucial factor and I expect her to chalk up yet another win.