Dzeko came off the bench to score twice in victory at West Bromwich Albion on Saturday.
Platt was pleased with the reaction of Dzeko to not starting the game.
He said: "Edin has been in superb form, not just goalscoring wise, and towards the end of last season he was coming off the bench and doing well.
"But when he has started he has done very well, as well. He is a top, top player.
"People should be disappointed when they are not in the team but the reaction you want when they come on is that they fight for their team and they have all done well."