He deserved it for beating Rafa at RG
And Djokovic beat Rafa at RG ... therefore ... you beat Rafa at RG - you get the line of your own ... $$$
Not exact subject of OP/me but ...
Federer had that run with Nike as well ... ended up in some sort of "dispute" with RF logo ...
Bottom line is ... BIg 3 are making money ...
And Stan Smith is making money ....
The rest of them ... not so much ... !!!