....In my opinion, Mr. Djokovic's flexibilty, while an asset to his technique (one of the best double-handed backhands), also causes a flaw in it. It is very subtle, but if one observe closely, you will find that he under-utilizes his hip. This is especially true for his serve. Due to an impressive amount of flexibility in his body, his shoulders turn independently and not coordination with his hip, causing more demand on his arms for power. I believe this is one of the primary reasons why he unfortunately dumps his serve into the net during crucial points. Unfortunately this tiny flaw in his technique has also affects him mentally, which causes him to hold back his hip even more--it has become a cycle.
I hope Mr. Djokovic can end this issue, among others, and become one of the great champions one day. One also has to give him credit for having the desire to improve his game....