Sampras and seemingly everyone else says that his loss to Federer at Wimbledon was due to being in a slump. Well, I think that's one factor but not the primary factor.
Consider that that same year in 2001 Sampras lost to Federer, he had made it to the finals of a masters series event at Indian Wells, the final of the US Open AFTER reaching Wimbledon, as well as the finals of Los Angeles and Long Island.
Compare Sampras' slumping 2001 to Federer's 2001 where Fed won in Milan and was a finalist in Rotterdam and Gstaad. Despite Sampras not winning any titles, he made it to the finals of more important tournaments especially at the US Open.
Let's also look at Sampras' record at Wimbledon. He had won Wimbledon the four previous years. Even in 2000 which was the beginning of his slump where he had only made it to finals of US Open and Queen's Club, he had won Wimbledon. The drop off from 2001 and 2002 is probably the steepest in his career considering he only won the US Open and Houston, but the point is Sampras' 2001 record was pretty damn good. And Federer beat him at this point in his career.
Also compare their rankings. Sampras was no. 6 in the world while Fed was no. 15. Obviously Sampras was on his way down compared to previous years, but the ranking tells it all: Sampras was the better player going into Wimbledon. Even though there is a ten ranking spot differential, I'd argue further that there's not much that separates a top ten v top 15 player. Yet Sampras still lost.
So the central question is, how far actually was Sampras away from his prime? If you look at the above data, I think you'll find it wasn't by much in terms of results. Federer wasn't nearly at his prime as the data shows and to compare them in their primes I believe you'll find Federer's 2004 to 2007 beating anything Sampras has shown. But if a slightly slumping Sampras can't beat a still green Federer, there's really no chance that he'd be able to beat Federer "in his prime."
Personally, I think Sampras lost a bit of motivation but that his game was still there. That's why he could still win the last two majors. But the overriding reason he lost to Federer and the cause of his "slump" was that the game was passing him by. Baseliners became more efficient at passing thanks to slower balls and courts as well as just training-wise so serve and volleyers died out. Just look at how many s and v players left and you'll see that that kind of game is no longer feasible. Then look at who Sampras lost to, not old guard players but newer guys like Safin and Federer.
The embodiment of this new era of tennis player was Federer, one who could hit any shot whether its a big serve, drop shot etc as well as see dimensions of the court. Federer's dominance until recently has shown that the other players have taken until now to sort of catch up to him.
So bottomline: Federer was nowhere near his prime (he even serve and volleyed most of the match) and still beat Sampras who wasn't far off from his prime.
Consider that that same year in 2001 Sampras lost to Federer, he had made it to the finals of a masters series event at Indian Wells, the final of the US Open AFTER reaching Wimbledon, as well as the finals of Los Angeles and Long Island.
Compare Sampras' slumping 2001 to Federer's 2001 where Fed won in Milan and was a finalist in Rotterdam and Gstaad. Despite Sampras not winning any titles, he made it to the finals of more important tournaments especially at the US Open.
Let's also look at Sampras' record at Wimbledon. He had won Wimbledon the four previous years. Even in 2000 which was the beginning of his slump where he had only made it to finals of US Open and Queen's Club, he had won Wimbledon. The drop off from 2001 and 2002 is probably the steepest in his career considering he only won the US Open and Houston, but the point is Sampras' 2001 record was pretty damn good. And Federer beat him at this point in his career.
Also compare their rankings. Sampras was no. 6 in the world while Fed was no. 15. Obviously Sampras was on his way down compared to previous years, but the ranking tells it all: Sampras was the better player going into Wimbledon. Even though there is a ten ranking spot differential, I'd argue further that there's not much that separates a top ten v top 15 player. Yet Sampras still lost.
So the central question is, how far actually was Sampras away from his prime? If you look at the above data, I think you'll find it wasn't by much in terms of results. Federer wasn't nearly at his prime as the data shows and to compare them in their primes I believe you'll find Federer's 2004 to 2007 beating anything Sampras has shown. But if a slightly slumping Sampras can't beat a still green Federer, there's really no chance that he'd be able to beat Federer "in his prime."
Personally, I think Sampras lost a bit of motivation but that his game was still there. That's why he could still win the last two majors. But the overriding reason he lost to Federer and the cause of his "slump" was that the game was passing him by. Baseliners became more efficient at passing thanks to slower balls and courts as well as just training-wise so serve and volleyers died out. Just look at how many s and v players left and you'll see that that kind of game is no longer feasible. Then look at who Sampras lost to, not old guard players but newer guys like Safin and Federer.
The embodiment of this new era of tennis player was Federer, one who could hit any shot whether its a big serve, drop shot etc as well as see dimensions of the court. Federer's dominance until recently has shown that the other players have taken until now to sort of catch up to him.
So bottomline: Federer was nowhere near his prime (he even serve and volleyed most of the match) and still beat Sampras who wasn't far off from his prime.