Yeah, one match defines a player. Watch Federer in his early 20s then come back to me.
Its true that Fed has lost some of his explosiveness with age, but I think credit should be given to Berdych who is capable of a very high level of play on fast courts. Would've been a slam winner in the 90s.
In his early 20's pink often lost to fast court players like Nalbandian. As surfaces got slower Nalbandian started declining and pink rose. Berdych, Nalbandian, Ancic, Tsonga suffered the greatest from slowness of surfaces. Tsonga was good attacking player initially when he broke out in 2008 but had to convert into another defensive player which he is not good at to match with slow courts.