Pep Guardiola has no doubt hat-trick hero Raheem Sterling can continue to improve but lauded the Manchester City star as "perfect" after his side's 5-1 Champions League demolition of Atalanta.

City fell behind to Ruslan Malinovskiy's penalty at the Etihad Stadium on Tuesday, but Sterling teed up Sergio Aguero to restore parity six minutes later in Manchester.

Sterling then won a penalty for Aguero to nose City ahead before half-time in the Group C clash, with the former running riot in the space of 11 second-half minutes.

England international Sterling should have added to his tally, but failed to finish when one-on-one with Pierluigi Gollini, though manager Guardiola hailed a faultless display from the winger – who has scored 12 goals in all competitions so far this season. 

"We were together for four years and I answered many times this question," Guardiola told a news conference when asked to comment on Sterling's development into a world class player.

"The credit is just for him. All of the credit. He can be better but he is perfect.

"His physicality, he is strong, he could play a game the day after a game, his regeneration is so strong. He is an extraordinary player. 

"He can play both sides, defensively he helps us a lot. He is an incredible player. It depends on him but he has the desire to do better."

Having slammed home from Phil Foden's tee-up just before the hour, Sterling raced onto Ilkay Gundogan's throughball to lash in his second before completing his hat-trick with a tap in from Riyad Mahrez's cross.

Sterling, however, conceded he should have helped himself to a fourth as he aims to become more clinical with his chances.

"It was difficult, especially them going man-to-man all over the pitch, so we had to stay patient," he told BT Sport. "I should have had four. Riyad set me up for the last one and I wanted to see if he was anywhere close to lay one on a plate for him. But yes, I've got to finish them off. There's no point scoring goals if you let in easy ones, so the penalty was a bit frustrating, but in this competition the good teams will punish you."