He's scored nine goals in 15 games plus two in five Europa League appearances.
"I am truly happy in Rome, as Lazio were what I had been looking for," said the 33-year-old.
"In this period I trained really hard and this is why I scored so many goals. I feel good psychologically and physically, while I get on perfectly with Coach Edy Reja.
"I don't want to give myself compliments, though, because I still really want to improve. If the fans have nicknamed me Kaiser than I'm happy, as such an important name means I'm doing well.
"Euro 2012 is the big objective I have in mind for next year, but it's not the only one."