Think about when Federer was upset by Roddick and Blake. In both cases, Federer had won the last huge string of matches (11 and 8, respectively) against them. They were both on a hard court. Federer was sloppy in both, and his opponent had given up enough to start swinging freely for the first time in years. Also, think of when Davydenko beat Nadal in Miami. He was not given good odds. It was a huge match. Still, somehow he was ably to be aggressive and not freak out. An upset is certainly possible. The big difference is that this is a slam. A "Haas at the French Open" situation is more likely than an actual win. Davydenko would have to get past Soderling first, too, which is probably a toss up at best. Anyhoo, while not likely, I think it would be a mistake to scoff at the possibility of an upset.