The Etihad Stadium boss said in November that the Argentina international was only behind the Real Madrid and Barcelona forwards in terms of talent, and lauded the former Atletico Madrid man as the best player in the Premier League.
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When asked whether he still believes Aguero is one of the top three players in world football, Pellegrini told reporters: "I continue to think that.
"They are both top players. Suarez has had the whole season playing, he has scored a lot of goals and Sergio has had a difficult season with injuries, but I wouldn’t swap.
"I think a lot of Suarez. He is a great player, not only a striker. He scores goals, but also plays a lot for the team.
"If you tell me I could change him for Sergio, no. I continue with Sergio."
Aguero has scored an impressive 26 goals in just 25 starts this season, but injuries have heavily restricted his appearances in the Premier League since December.
As well as praising his fellow South American, Pellegrini also hit out at Chelsea, suggesting it would be disappointing if Jose Mourinho's side won the league and claiming both his own side and free-scoring Liverpool ought to be "rewarded" for their attacking football.“It would be very disappointing, for football, for the fans, for everyone,” said the Chilean. “I think that the most attractive football, the more goals you can score, should be rewarded.
“I’m not saying it’s not important to defend very well. Football is attacking and defending. But I think that big teams must play as big teams.”