The Argentine missed most of last season after falling out with City boss Roberto Mancini due to an incident in their Champions League match at Bayern Munich, where Tevez allegedly refused to warm up when requested.
However, Tevez returned to help City on their run-in to the Premier League title and grabbed the club's first goal of the season against Southampton on Sunday. Mancini has only managed to add Jack Rodwell to the champions' squad so far this summer, but Kompany says that having Tevez back is like a new signing.
"Carlos is recognised by everyone as one of the best strikers in the world," said Kompany.
"People talk about new signings but having Carlos at his best level, which he wasn't last season because he was away for most of it, is just like one.
"I still say we have improved."
Next up for Manchester City is a trip to Anfield to take on Liverpool on Sunday.