Would Davydenko have beaten Federer if it wasn’t a Grand Slam?

Question

Nikolay Davydenko has proven he can beat Roger Federer and Rafael Nadal on the ATP Tour, but playing the best of five sets at a Grand Slam is a different matter. You’d think that at a set up and leading 3-1 in the second (as was the case in their Australian Open semi-final) if had been anywhere other than a major, the Russian would have found a way to get across the line.