Sterling opened the scoring with a superb curling effort and finished of a well worked corner routine to add a second quickly after half-time.
He wrapped up his treble with a close-range finish on the rebound after seeing his initial penalty saved by former City goalkeeper, Angus Gunn, after Liam Delap was brought down in the area.
“He made a fantastic game,” said the City boss at his post-match press conference.
“Especially after the goal - he was so aggressive and direct. He made a fantastic goal [and] the second one he was there.
“He has been an incredibly important player in all these seasons, with the amount of goals and assists. He always creates something.
“When he has confidence, he is a really important player.”
The midfielder missed out with a problem he picked up after the midweek victory against Brentford and, whilst Guardiola is hopeful it won’t keep him out long term, he admitted he faces a wait to see whether the 26-year-old will be available for Tuesday’s Champions League game against Sporting Lisbon.
“I hope not. We will see,” he replied when asked if the injury was serious.
“I don't know if he will be ready for Tuesday. After Brentford we trained, and he was uncomfortable.
“He was not able to play today, but hopefully in the next days [he can].”