Sterling has scored five goals in four Premier League games for City so far this season, and impressed for England over the international break scoring two goals and setting up three more in Euro 2020 qualifying wins against Bulgaria and Kosovo.
"I am so happy for him for the way he is playing," Guardiola told a news conference. "Hopefully he will not listen to these kind of things; it will be good for him.
"Nobody can compare with Cristiano or Messi. Everything that has happened to him is good because he has an incredible work ethic and is an incredibly nice guy."
Guardiola also confirmed that defender Aymeric Laporte will be out for five to six months with a knee injury.
Laporte, 25, sustained the injury in City's 4-0 victory against Brighton at the Etihad before the international break.
Sources told ESPN FC that the France international would be unavailable until 2020 following surgery to repair cartilage and meniscus damage in Barcelona.
City travel to Premier League newcomers Norwich City on Saturday before kicking off their Champions League campaign against Shakhtar Donetsk on Wednesday.