The question is whether Serena is injured, or is she injured? With the Williams and Henin, you never really know.
But Serena fights hard out there and depending on the nature of the injury, she can win this match. I'm not hedging my bets with that "depending" clause, I'm just saying that Jelena Jankovic can be a joy to watch but she hasn't proven herself to be the most mentally tough player out there. In fact, she isn't mentally tough at all. So I'd bet even money on Serena winning anyway.