As long as he gets his fair share of goals I won't complain about his work ethic defensively. I don't see why he should chase the ball by the corner flag when he's already 10-15 yards behind Terry. If he's there closing him down then the whole team needs to push up along with him and that was clearly not the strategy on Sunday. Roque didn't work his socks off either imho, though he did win his fair share of headers that could've created some danger if they had hit the path of Benni.
As for his lack of work ethic affecting his teammates...this is his second season for us and nobody seem to be easing up, on the contrary they seem to be working harder as a unit than ever. Matty knows he still has a lot to learn and that he'll get his chances in the right games, and if he continues to grab his chances and improve he'll be the regular starter and Benni will be on the bench - that's when you're guaranteed a dent in morale.