Aguero joined big-spending City in a £38 million ($62 million) transfer on Thursday, but Forlan is convinced his old pal would have been better suited to playing for Chelsea, who were also considering a move for the highly-rated Argentina forward.
Former Manchester United striker Forlan believes Aguero's skills would have fitted perfectly into Andre Villas-Boas's attacking philosophy and he is not so sure City's more cautious style will bring the best out of the 23-year-old.
"It was no real surprise to see him leave, but I thought it would have been to a different club. Chelsea's game and squad are more suited to his style," Forlan told The People.
"And of course I am a Manchester United fan, so his decision to move to City is also painful for me."
Forlan also warned Aguero that it can take time to adapt to the unique demands of the Premier League, a problem the Uruguay star experienced himself during a miserable spell at United.
He scored only 10 goals in 63 appearances between 2001 and 2004 and never looked comfortable playing for Sir Alex Ferguson's team.
In contrast, Forlan has thrived in Spain with Villarreal and Atletico and he is concerned Aguero may suffer the same fate.
"I know City are now one of the big clubs in England, so I wish Sergio luck. But I know from my own time in England that the Premier League is not like La Liga," Forlan said.
"The key for him will be how he adapts to the style of the game and also the country.
"He can be a success because he is a star. He can be a king at any club.
"The best asset of Aguero is the number of goals he scores. He is a killer and could also destroy many defenders with his dribbles.
"Personally, it is bad news to me because I will now miss a big companion in attack at Atletico.
"He is not the tallest, but that is not a problem, and neither is the hardness of the English defenders."
Source: AFP
Source: AFP