Marc Guehi didn't dress it up. City's opening 45 minutes against PSG, he admitted, fell well short of the standard expected at the Etihad.

The defender fronted up after the European champions left Manchester with a 4-2 win, a result that handed Enzo Maresca his first defeat since taking charge.

By the interval, the visitors had scored three without reply. Desire Doue, Ousmane Dembele and Vitinha did the damage, with Doue and Dembele striking just 99 seconds apart to leave City's backline reeling.

Guehi didn't shy away from his own part in it.

"First half we need to do a lot better, myself included, for the first two goals," he told City Studios.

His explanation for the collapse was straightforward. PSG simply wanted it more in the duels.

"I think they were a bit more aggressive and won a lot of one-on-one duels in the first half, which allowed them the platform to score those goals."

Playing at home, in front of their own supporters, made the performance harder to swallow.

"More the fact that playing at home, it's not really acceptable, that performance in the first half in front of our fans. I'm just really glad everyone reacted in a positive manner and at least came out fighting."

React they did. Maresca made three changes at the break and City emerged a different proposition, carving out 21 attempts on goal after the restart.

Erling Haaland scored twice and struck the woodwork as an unlikely comeback briefly flickered into life. But Maghnes Akliouche found the net for PSG's fourth, and the fightback ran out of road.

For Guehi, the lesson is simple. City can't rely on outscoring opponents in a shootout every week.

"If we defend better, we give ourselves a good chance of winning the game. So you can't always say we have to score five or six goals to win a game."

He added a warning about the fine margins at this level.

"Any moment you go 50/50 in those challenges or not following your men, they'll exploit it."

Ipswich Town visit the Etihad on Saturday, and City will need to show the second-half version of themselves from the start.