Sterling netted his second goal in three Premier League appearances this season, cutting inside to dispatch a clinical finish in the eighth minute at the Etihad Stadium.
City needed a superb long-range strike from Sterling's England team-mate Kyle Walker to seal victory after DeAndre Yedlin sent Newcastle in level at the break.
The City boss denied Sane's attitude was the reason for his omission, despite speculation to the contrary, but went on to outline the value of Sterling's all-round game to his team.
"He made a fantastic goal and he fought a lot," he said.
"Especially in the second half he played so clever. He moves the way we need him to move to help the team to be stable.
"The wingers are so important to make stability in our team and he did it quite well."
Sane's brief appearance in the 1-1 draw at Wolves was error strewn, although Guardiola pointedly stated he would continue to judge his players primarily on work rate.
"He played 10 or 12 minutes, he tried. He was not precise but he tried," the former Barcelona head coach added.
"They [the players] know me. They convince me [and] I am satisfied the moment they run and do everything.
"The mistakes without the ball [and when] taking decisions – it is part of the process. So, it's no problem."