I think this is a good style match up. Come forward high work rate guy versus come forward high work rate guy. I like it! I think that Diaz at this point in his career has the capacity to last longer then Hatton if he is able to avoid Hatton's body attack. But I don't think he'll be able to do that. So i would say Hatton by close UD.
Just like what I said on the Diaz vs Cotto thread . . . Diaz cannot back up Hatton . . . . and once Diaz cannot do that he is doom to lose. It's gonna be a worse beating for Juan than what Kotza Tzsyu had experienced. Hatton by K.O. before 6th.
hattons main asset at 140 is that he is usually physically stronger than his opponents. the same goes for a fight against diaz. hatton would probably have him backing up, where i dont hink diaz would be comfortable.