In City's crucial last three games, when they have seized control of the title race from Liverpool, Dzeko has scored five - doubles against Villa and Everton, and another at Crystal Palace - and now has 26 for the season overall.
Pellegrini said: "I think it was very important at the beginning of the season to have a good squad - more than a team - a squad.
"At this moment Edin is in a very high level of performance, he is doing very well.
"In other moments it was Alvaro Negredo or Kun Aguero, so I think all the players are involved."
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