I think he didn't account for Calzaghe's jab as much as he should have, Calzaghe was able to straighten himself out in the second half of the fight behind the jab. In the first half Calzaghe was just countering over all of Joe's posturing/punches but then found that more difficult later on. Think he should have abandoned the countering and become more offensive by getting in and out with 1 punch like he did in the early goings.

Still, I think he won but obviously not convincingly.