The two knockdowns did him in. However, you could make a case that Berto landed the more telling blows and if you don't like all the Guerrero hit and holding tactics. Berto just looked like the beaten fighter at the end as well. Berto needs a real trainer if he continues to compete at a high level, as his corner seems to put more faith in his athletic ability then giving him any real sound advice. He definitely needs to fight more often as well. If Berto had a jab (and an adjustment plan), the fight could have been different. Embarassed himself by trying to do the shoulder roll.
G was working the free hand while most of the time B was content to let him and take a rest. We've seen this before in judging. Bring it or go home a loser. Shouldn't be a surprise. No one in Berto's corner was surprised by the results. If nothing else take a clear look at that corner from the moment the bell ends the 12th on. They knew he lost and it showed CLEARLY in their faces.
I could see the fight being scored even on rounds, but the 2 KD's made it impossible for Berto to win. I scored it 7-5 Ghost, plus the 2 KD's, so it wasn't a close score...even though it was a semi close fight. I can't fathom a scenario in which one would score this fight for Berto.