Federer's competitive instinct is unreal. You see him in interviews seeming so relaxed and he will say he just wants to play tennis and see what he can do now. Then he gets on court in a big match and all the hatred of losing comes right back.
Murray just needs to keep playing well here because imo, Federer won't dramatically increase his level. If Murray plays a strong set, he is still favourite for the match.
Champions deserve whatever they win playing within the laws of the game