I think that may have been more to do with the mental and physical anguish of the last 13 months recovering from the injury. Just a pure release of emotion.
He seemed to get more confident as the fight went on to be fair but then Diaz did nothing except make a show of himself for saying he thought he won all 5 rounds. That's his corner's fault though, they kept telling him he was doing well.
How thin did Silva's leg look? Fair play it's only 13 months since that injury and he was using it for some good kicks, but man did it look thin.
Also, GSP is the GOAT by some distance, he may not always have been the most exciting in terms of KOs etc. but he beat everyone he fought, and nearly all of his fights were massively one sided in his favour despite fighting the best guys.