No one accused Nadal of being a sore loser for his comment after MC. Every player is entitled to give any explanation they see fit for the loss. Of course, if you say you were "injured" or "not 100%" after every second loss, you lose credibility and people think you are just crying wolf and being a sore loser, as it happens in Nadal's case quite often. I thought Novak was very gracious at the net with Dimitrov and also in the presser. His yelling at the crowd (if what he said is actually as bad as some of the translations) comes across as classless (not that the crowd was any classier) but that doesn't make him a sore loser.