Pellegrini has already said he believes the in-form Aguero is behind only Lionel Messi and Cristiano Ronaldo among the game's current greats.
The 25-year-old Argentinian has been outstanding this season having scored 15 goals in his last 12 games and 16 in total.
The prolific duo of Barcelona ace Messi and Real Madrid inspiration Ronaldo have been vying for the title of the world's best player in recent years but Pellegrini believes Aguero can join that elite company.
Pellegrini said: "We hope. That is what we are working on every day and what he wants.
"The ambitions of Sergio will be very important if he can arrive at that level."
Pellegrini, who took charge at the Etihad Stadium in the summer, previously encountered former Atletico Madrid forward Aguero during his time in Spain.
The ex-Villarreal, Real Madrid and Malaga boss believes his improvement since then has been considerable.
Pellegrini said: "He is a better player because he is older.
"He arrived in Spain when he was 18 or 19 years old. He was always a very important player, a top player, but this year he is trying to work a little bit more without the ball.
"You see, three or four of the last goals we scored are because he is doing a good job pressing on their defenders. I think he is more complete."
Pellegrini is certainly in doubt Aguero, signed by City for £38million in 2011, is the best player in the Barclays Premier League.
The Chilean said: "I said last week after Messi and Cristinao Ronaldo he is the best. Both are not playing in the Premier League, so he is."
Aguero has formed a formidable partnership with summer signing Alvaro Negredo this season with the pair having scored 27 goals between them.
The team as a whole has also been in fine goalscoring form of late with the net hit 22 times in the last four home games alone, including a 6-0 thrashing of Tottenham last weekend.
Swansea are the next side to visit Eastlands hoping to contain them and they will be short of firepower themselves with strikers Michu and Wilfried Bony both out injured.
Pellegrini claims he is reading little into that.
He said: "I don't think it will be easy. Michu is very important for them but we have other players injured.
"Swansea are a very strong team. They play very well. After Manchester City they are the team with most possession in the Premier League.
"We must play a very good game if we want to win here at home.
"Because we won against Tottenham doesn't mean we are going to win against Swansea."
City were below par in their Champions League clash with Czech side Viktoria Plzen in midweek but Pellegrini had made seven changes after the Spurs game which showed them at their very best.
City are surprisingly yet to click away - having lost four times in the league on their travels - but Swansea could be in trouble if they get back into the stride that crushed Spurs.
Pellegrini said: "I expect the same effort, I expect the same team.
"We will try to have the same names, the same men. That is very important.
"I think the way we played against Tottenham is the way this team must play, especially the second half.
"We are not always going to score seven goals. If we play not only scoring but pressing with speed, it is the team I want to see every Sunday."
Attention will again be centred on Pellegrini's choice of goalkeeper for the game.
Joe Hart was recalled against Plzen after being left out for five games but Costel Pantilimon had previously done little wrong in his place.
Pellegrini declined opportunities to state which keeper would play this week, although he did say Hart's impressive midweek performance would enter his thinking.