Kessler was landing with some vicious right uppercuts. Calzaghe adjusted defensively and wasn't getting hit with them as the fight progressed. Hopkins used to throw uppercuts quite a bit (Trinidad, Johnson, Lipsey, Brown), but not so much anymore. Maybe Hopkins can exploit this if he has the timing to do so and if Calzaghe shows vulnerabilities to the uppercut during the fight. I look for the counter right hand to be Hopkins' most effective punch.
Kessler wasnt landing it a lot in the second half of the fight. Calzaghe was dodging it well, and made the necessary adjustments