Anyone who has played a match against the Djoker would know that it this a regular trick of his. That's not to say his physical distress wasn't genuine (he really did fall and scrape that thumb lol and almost rolled his ankle), but I'd say he exaggerated it a bit, just like soccer players do doubling over in pain when 'tripped' over by someone.
Murray of all people should know this by now, he's played against the Djoker how many times now? 100??
It's not bad sportsmanship, he didn't take it up the next level and call medical time out like Nadal seem to do at crucial moments, and he didn't hold up the game. Murray, on the other hand.. smashing the ball into the roof, systematically demolishing all his racquets one by one while Djoker celebrates his win.. lol what awesome sportsmanship aye the mega sook.