Just rewatched this fight this morning. Joshua was out of breath after the first round and was legit gassed by the end of the third. He obviously didn't prepare for the fight at all. Even after he knocked down Ruiz he didn't go in for the kill afterwards. I'm not guarenteeing he wins the rematch but if he doesn't underestimate Ruiz this time and works on his endurance he can knock Ruiz out cold sometime in the earlier rounds.