Re: I have discovered the key to success.
If it is indeed truly helping you play better tennis by not practicing/training, then congrats, you are part of a very small minority. I mean really, you should have changed the title to "I have discovered the key to success for me," because what top player ever gets far without practice? Sure we all know, McEnroe barely practiced but remember, he played a lot of doubles so it probably balanced out anyways. Lendl trained hard for hours on end, Federer & Nadal the same, etc. Perhaps you may be training too hard is what may have caused you problems in the past? If you compare Federer and Nadal on the practice courts, their intensity is very different, yet they both produce magic in real matches. Federer seems to just enjoy the tennis so he plays on the practice courts very casually while Nadal plays almost as hard as he does when playing an actual match. I personally take a Federer-ish approach when practicing. I use the time of practicing to play trick shots, to concentrate on the feeling of the ball, making sure my timing is okay and most importantly keeping the serve in tune which is something I heavily struggle with (especially the toss) when I haven't had much practice. I don't really push myself when chasing balls or even hitting. At the gym I'll push myself, but I do find that on court praciticing, it is best spent having a good time for me.
Federer / Haas / Safin / Gaudio / Kuerten / Youzhny / Nadal / Gonzalez / Ljubicic / Hewitt / Soderling / Wawrinka / Coria / Nalbandian / Kohlschreiber