Adam Johnson had made his deal. He won the Premier League and the FA Cup and exchanged the possibility of further glory with Manchester City for the certainty of playing regular games.
Unfortunately, it meant he would sometimes be playing in games like these, ones in which he was bypassed and his team outplayed. As the match wore on, Johnson felt increasingly ill and he was taken off to be sick in the dressing room.
For the first time the men in blue he left behind looked like what they are, champions of England. Sunderland had been flattered by the fact they came to Manchester unbeaten and they were surely flattered by this scoreline. Had Mario Balotelli not stalked down the tunnel after being substituted, the afternoon would have been near-perfect for Roberto Mancini.
David Silva chipped on to the Sunderland crossbar. Carlos Tevez shot inches wide. Danny Rose cleared off the line from Micah Richards. This is a fixture with goals – the last four meetings here have produced 21 – and Sunderland were fortunate there were not more.
"We actually needed the second to settle us down, even though we were controlling the game," said City's assistant manager, David Platt. "Then we started to play with a lot more confidence, freedom even, because the fear factor had gone.
"I don't think we have been stuttering as much as some people have made out. Chelsea have flown out of the blocks like Manchester United and we did last season but, if you look at the equivalent fixtures and substitute Southampton for one of the relegated clubs, we are actually better off than we were in the same games last year."
Because on Wearside, Martin O'Neill is considered "one of us"; because of the way he salvaged the club last season and the aura that surrounds him, this defeat can be taken in his stride. However, a similar performance in Sunderland's next fixture, the Tyne-Wear derby, may not be so easy to brush off.
And yet as the sides kicked off City had looked vulnerable. Mancini made seven changes to the side that had been battered in midweek. Joleon Lescott, a defender the City manager does not appear to entirely trust, was paired with Micah Richards, who has long been discarded by England.
City then did to Sunderland what Borussia Dortmund had done to them. Joe Hart was required to make only one of the reaction saves that had denied the German champions. The game was probably over after four minutes when Carlos Cuellar conceded a foul close to the Sunderland area. There was a debate between Aleksandar Kolarov and Balotelli as to who would take the free-kick.
Like most things yesterday, it was an argument Balotelli lost and from the moment Sergio Aguero came on to replace him, City attacked with increasing fluidity. Mancini pronounced himself "happy" with Balotelli's contribution while adding that "he can do better".
Kolarov's free-kick was as good as the one he had taken against Real Madrid. That had been directed perfectly across the face of Iker Casillas' goal, this one curled round the near side of the wall and beat Simon Mignolet at full stretch. A few minutes from the finish, a similar free-kick, this time delivered by James Milner, gave Manchester City the scoreline their dominance deserved.
This was Kolarov's fourth goal in five matches for club and country and here he delivered a complete performance, tackling Johnson superbly. On the hour Kolarov played a one-two with Silva and then sent in a low cross that was met by the inrushing figure of Aguero.
The Argentinian averages almost a goal a game at The Etihad, a stadium that should come to mean as much to him as the Monumental in Buenos Aires or Madrid's Vicente Calderon. What it will come to mean to Balotelli is harder to say.
Manchester City (4-2-3-1): Hart; Zabaleta, Richards, Lescott, Kolarov; Milner, Barry; Silva (Rodwell, 90, Y Touré, Balotelli (Aguero, 56); Tevez (Clichy, 86).
Sunderland (4-4-1-1): Mignolet; Gardner, O'Shea, Cuellar, Rose (Vaughan, 61); Johnson (Saha, 69), Colback, Larsson, McClean; Sessègnon (Campbell, 83); Fletcher.
Referee: Lee Probert
Man of the match: Kolarov (Manchester City)
Match rating: 6/10