Manchester City manager Pep Guardiola says his side "forgot" to show up during the first half of their 3-1 Champions League defeat by Monaco but believes their exit from Europe's premier competition will prove to be a good learning curve for the club in the long-term.

City produced an abysmal first half display against Monaco and were deservedly 2-0 down at half-time courtesy of goals from wonderkid Kylian Mbappe and Fabinho.

Guardiola's men rallied after the interval and swung the tie back in their favour through Leroy Sane, but their defensive frailties were highlighted once more as Tiemoue Bakayoko headed in the killer goal from a set piece with 13 minutes to play.

City huffed and puffed but couldn't conjure a reply and were subsequently knocked out on away goals, with the aggregate scoreline tied at 6-6.

Guardiola praised his side for their "exceptional display" in the second period but bemoaned the dross served up in the opening 45.

The former Barcelona boss, who before this season had always reached the last four of the Champions League as a manager, was understandably disappointed but hopes his side can use the chastening experience at the Stade Louis II to develop and grow.

'We forgot to be there'

"We played an exceptional second half but the first one we forgot to be there," the Manchester City boss said. "We want to be an aggressive team with and without the ball. The second half was much better.

"We will learn. We don't have a lot of experience in this competition. We had the chances to scores lots of goals in the second half."

John Stones echoed the sentiments of his manager and believes that City "were not clinical enough in both boxes". The former Everton defender also condemned their first-half display but thinks they should have gone through to the last eight of the competition.

Pep Guardiola
Pep Guardiola says Manchester City 'forgot to be there' in the first half in Monaco Getty Images

"We were very sloppy - not up to our standard in the first half," Stones said. "We wanted to correct that but we weren't clinical enough in both boxes. We didn't score enough and weren't defensively solid enough.

"The second half didn't reflect the whole scoreline. We were the Manchester City people know from this season. We should have scored more. It is a difficult one for us to take. We should have done better and deserve to be in the next round.

"The gaffer was saying before that the more and more he plays the Champions League it is about the set pieces. Real Madrid scored from two last week and went through. We weren't solid enough."