Pellegrini lauds 'improving' Aguero
The Argentina international was at his brilliant best at the Stadium of Light on Wednesday, scoring two goals and setting up another as City came from behind to beat Sunderland 4-1 in the Premier League.
His double, and goals from Stevan Jovetic and Pablo Zabaleta, ensured the champions remain six points behind leaders Chelsea and are now four better off than third-placed Southampton.
Aguero now has 19 goals in all competitions this season and Pellegrini believes there is plenty more to come from the former Atletico Madrid man.
He said: "I am very happy for Kun because he is working hard. I always say he is too young. He is only 26 years old and I think he can improve every day.
"He wants to do it and at this moment, it is difficult for defences to stop him. He is playing a very high performance but there are so many years left for him to strengthen.
"Before he started scoring in these games in a row, I thought he was in the top five players in the world. I am very happy for him because he's playing well as well as scoring."
Pellegrini is confident City, who impressively beat Southampton 3-0 on Sunday, are heading in the right direction.
The Chilean added: "This team is not just about Aguero though.
"He is a very good player but the team have come here again and played the same way we did last season - we dominated the game and we have players in high performance.
"We are playing very well and we repeated the same performance we did against Southampton - we were very strong.
"It's very important to be an attractive, offensive team for the fans."