Re: Djokovic hasn't beaten a fellow member of the Big 4 since early June...
I always felt like a true no. 1 should never lose a single match to any other tennis player throughout his whole career. Only then can you show truly undisputed dominance. In fact, it would be even better if this real no. 1 never lost a single point in his whole career. Again, that would show truly unrivaled dominance.
I hope one day to see that sort of player, and this current top 4 will comparatively look like a bunch of jokes.