Tactics that work against Fed

I have been analyzing Federers matches at the u.s open so far and noticed a few things that may be pertinent . I am studying statistics so of course most of my findings are based on numbers on what works well and what doesn't . From what I observed with his match against Kiefer ,Federer doesn't like it when you slice the ball low as he does so often against his opponents . Why does Federer continue to slice the ball , maybe it's because he knows it's a shot that would be tricky if it were executed against him. It's the same reason why someone decides he wants to be a serve and volleyer , he prefers playing at the net rather than staying back . When you slice the ball very low like a steffi Graf slicer it prevents someone like Fed to rip an easy winner on his next shot . I noticed Agassi used the slice shot effectively throughout his match , especially on his first and second serves . It is also important to note that Agassis first serve in the second set was around 40 % and relied heavily on his second serve slice shot . Federer prefers a fast pace serve so he can chip it back , slice serves to the body are more tricky for him , as he has to do something more with the serve . In Hewitts last few matches with Federer , he has learned to use the slice shot more effectively and often cuts the point short by charging to the net . Another thing I noticed is that when Kiefer playes Federer , he often hits his shots to the centre of the court and deep . When other players play Fed , they go for too much by trying to hit the lines and making him run . If you watched his match against santoro you'll notice how often he would win points by using both forehand and backhand slice shots . So if I were playing Fed , I would do the following :

1) use slice serves to the body but mix it up for obvious reasons

2) slice the ball low and deep to the centre of the court

3) mix up the pace of your shots , like what Fed does to all his opponents .