Aguero is ready to face West Ham today eager to continue his superb start to the season, which as seen him score 11 goals in as many games, including four against Tottenham last weekend, has reignited debate over his standing in the world game.
A year ago comparisons with the likes of Cristiano Ronaldo and Lionel Messi were common but injuries then hampered Aguero throughout the second half of last season.
Those problems, which also affected the Argentina international at the World Cup, now seem behind him and he appears close to his blistering best.
But Pellegrini expects the 26-year-old to get even better and eventually surpass the levels of those currently regarded as the best.
Pellegrini said: “Sergio is a young player, he has a lot of years to improve — three or four years more than other players. It just depends on what he wants to do in the future. I think he has all the conditions to do that.
“I don’t think it is the best I have seen from Sergio. I was always sure he would return to his normal performance but I think he can get even better.”
Aguero has had his say on Mario Balotelli saying he believes the Italian is insecure.
During his time at the Etihad Stadium, the Italy striker set off fireworks in his house, threw a dart at a youth team player and amassed parking fines which ran into thousands of pounds.
After scoring one of City’s goals in a 6-1 win over Manchester United in 2011, Balotelli famously lifted his shirt to reveal the message ’Why Always Me’ — which Aguero thinks the 24-year-old did because he felt insecure.
“I still miss Mario Balotelli being at City. Even though he used to drive us all nuts,” Aguero said in his new book, ’Born To Rise: My Story’.
“We all knew Mario was a little crazy. The thing was, Mario was crazy when he wanted to be. He’d do daft things whenever he felt like it because he thought he could.
“A lot of his behaviour, I feel, came from a feeling he had that he was somehow different and maybe a little insecure.”
“He used to say that nobody loved him and I’m sure he believed that was true, though it was anything but.“Nobody knew he had that t-shirt on when we played United at Old Trafford – he must have hidden it beneath a vest. If we’d known we’d have told him to take it off.”
Meanwhile Hammers boss Sam Allardyce (pictured) believes on-loan midfielder Alex Song will be a “Yaya Toure-type signing” for West Ham this season.
Song swapped the Nou Camp for Upton Park when he moved from Barcelona in August and the 26-year-old has helped lift the Hammers to fourth.
West Ham’s strong start will be given a rigorous examination today and when asked about his opponents’ world-class stars, Allardyce said: “We’ve got that type of signing in Alex Song.
“That’s a Yaya Toure-type signing for us. He’s a top quality player of the highest calibre and he’ll provide the sort of service our front line need. He links everything together very well so we’ve got a top quality international player that’s played for Arsenal, for Barcelona and in the Champions League.
“He’s being slightly overshadowed by Enner Valencia and Sakho at the moment but he’ll have a big impact for us. Everyone has a lot respect for what he’s done before. He hasn’t hit top form yet but he’s a major influence.”