The ex-Real Madrid boss has begun his new career with the former Premier League champions following his switch from La Liga outfit Malaga.
"He's moving to a country where they let you work," Forlan told FourFourTwo magazine. "He'll have pressure, but not the internal battles he had at Real Madrid. I think he'll be a success and City's players can only learn from such a fine coach."
Forlan played under Pellegrini while at Villarreal.