Manuel Pellegrini believes Sergio Aguero is not yet at his best for Manchester City this season.
The Argentine striker scored all four goals in last weekend's 4-1 win over Tottenham, to take his Premier League tally to nine, before netting the opener in the 2-2 Champions League draw at CSKA Moscow on Tuesday.
Despite this free-scoring form, Pellegrini is expecting Aguero to take the next step and become an even better player as the 2014/15 season progresses.
"I don't think we have seen the best of Sergio," Pellegrini said.
"I've known him for many years, since when he was in Spain. He was an important player in 2011/12 and last year he was very important in the first part of the year.
"After that it was difficult for him, but I was always sure he would return to form. I think he can do better."
Former Atletico Madrid star Aguero has scored 11 goals in 11 appearances for the reigning English champions this season following his 28-goal campaign from 34 outings last term.
