The atmosphere inside the Etihad stadium was electric as the supporters roused for a rendition of 'Blue Moon.' It never quite reached those heights on the pitch, but it was an absorbing match all the same.
Then, in the post-match press conference, Manuel Pellegrini let rip.
It wasn't a rant, far from it, he sat relaxed in front of the world media and calmly suggested that Swedish referee Jonas Eriksson wasn't "impartial."
Around the room, journalists were double taking and asking those next to them if they had heard him correctly. The laid-back exterior and softly spoken delivery of his words made the moment even more surreal.
Now he was accusing a Champions League referee of bias.
Pellegrini is an intelligent man and he rarely said anything controversial in nine years in Spain.
However, he did get riled at Malaga's elimination from the quarter-final stage of this competition 12 months ago, per ESPN.
They did not want us in the semi-finals.
After it went 2-1 for us, there were so many refereeing mistakes. The third goal was a hammer blow for us. There were two dismissals, and there was also their offside in the act of making it 3-2.
In the final 10 minutes, we were so impaired (by the officials). In such conditions, everything becomes very difficult.
Those were extenuating circumstances; only days earlier he had been at his father's funeral and it was looking like they were going to win the tie against Borussia Dortmund until a late turn around, via BBC.
Ironically, Eriksson was in charge of the first leg at La Rosaleda, where Malaga held their German counterparts 0-0.
Here, Pellegrini blamed the officials for prejudice and incompetence simultaneously in the post-match press conference, as noted by BBC Sport.
Well I think that the referee decided the game because before the penalty there was a foul on Navas, when he was three metres from the play, so he saw it without any problems.
From the beginning I think that the referee was not impartial to both teams. So he decided the game with the foul he didn't give. Then, after with the penalty of Demichelis that was not a penalty as it was outside the box.
At first glance it did look a penalty, such was the speed that Lionel Messi glided past Martin Demichelis. The replay showed initial contact wasn't in the area but former referee Graham Poll argues that a spot-kick was the right decision, via The Daily Mail.
There were moments in the game when what seemed like innocuous challenges were awarded free-kicks. The TV cameras often revealing that the Swede was in fact correct.
A two-footed tackle by Aleksandar Kolarov gave the official an earlier excuse to reduce City to ten men—with the referee producing just a yellow card—before Demichelis denied Messi a goal-scoring opportunity.
City had played well overall, they were organised and had a clear plan that was limiting Barcelona to possession away from Joe Hart's goal.
Pellegrini's comments just diverted attention away from their decent, if not, naive performance.
"Barca had a lot of the ball, but where we wanted," conceded Pellegrini.
Overturning a two-goal deficit at the Camp Nou will be extremely difficult in the second leg, so the chances of facing PSG and Sweden's most famous player Zlatan Ibrahimovic in the latter rounds is unlikely.
"I think it was not a good idea to put a referee from Sweden in such an important match," declared the Manchester City boss in his press conference.
When asked what was the relevance of the referee being Swedish, he replied:
There's more important football than in Sweden in Europe. Between two important teams, I think that kind of game needs a referee with more experience.
But I repeat that I think the first mistake was putting a referee that damaged Barcelona in the group stages.
Proclaiming that Eriksson was trying to settle an old score or that he is not at the desired level is wrong given the nature of the events and Manuel Pellegrini should know better.