Changing from orthodox to southpaw, Adesanya made the most of his height and reach advantage and made Vettori, who had no choice but to plod forward, look two-dimensional in comparison.
After Adesanya announced himself with such a charismatic performance in his debut, UFC president Dana White watched closely cage-side.
His constant feinting and inside kicks to Vettori's legs sapped his opponent's strength, but he couldn't find the knockout blow despite showing an impressive array of strikes from fists and feet.
Vettori said before this middleweight fight that one of his attributes was his "marble head", and it held up well apart from a cut above his right eye. He also had to cope with an accidental eye poke in the first round and a beautiful right elbow from Adesanya in the second.
"Hats off to him, his marble head held up like he said," Adesanya said in the octagon afterwards. "He had better head movement than I anticipated. I don't know, a win's a win but I'm not happy with it."