The French midfielder failed to produce his best as Manchester City claimed the spoils in a 2-1 victory with Pep Guardiola's side running riot in a one-sided first half.
But Ibrahimovic is adamant the critics will soon be silenced and that their views are fuelled by jealousy.
"All the jealous people who talk about him will swallow all of the words they have said about him," Ibrahimovic told SFR Sport.
"He will only improve and will get everyone behind him.
"My relationship with Paul is easy: I speak, he listens. Paul is a player with a lot of talent."
Despite a world record fee, Ibrahimovic believes an element of patience is needed with the 23-year-old.
"Now, you have to be realistic, people are putting a lot of pressure on Paul," claimed the Swedish forward. "His transfer created a huge amount of buzz.
"I didn't know Paul before and, now that I do, I can tell you he's someone who works enormously. He really wants to improve and he has a super attitude. But you mustn't forget he's young. That's all I can say."
Jose Mourinho will hope his side can bounce back quickly after their Manchester derby blues with a trip to Feyenoord in the Europa League on Thursday next up.