He's on the bench for a reason mate. And it should have been a lot sooner than he was put there.The entire team went to **** after the first goal, if he'd have started the game and been awful then you might have a point. I'm not sure what he was supposed to do while the rest of the team pretty much gave up shortly after he came into the game.
And don't blame his substitution for the collapse, one stupid tackle from a good player caused that, Mason's introduction was purely coincidental.