Manchester City is staring Champions League elimination in the face after a rash tackle from the Argentine defender turned the tide in Barcelona's favor
Three years ago, outside the Etihad changing rooms after City's last European knockout tie at this ground, Nigel de Jong puffed his cheeks out, looked down at the floor and told us what we already knew.
Mario Balotelli's sending off against Dynamo Kiev, the red card that changed the game, had cost his side and sent City crashing out of Europe.
And so it goes again. This time Martin Demichelis, the Argentine whose selection drew furrowed brows before kickoff and shakes of the head come full time. The 33-year-old, whose 53rd minute hack on compatriot Lionel Messi gave Barcelona the penalty it needed to open to scoring, had cost his side.
Sympathy may be in short supply for Demichelis but his wasn't a moment of madness or petty frustration. The challenge, trying to stop the unstoppable Barca man, was borne out of desperation. Messi was away, advancing towards an almost inevitable opener and a goal that would completely change the complexion of a tie which was hitherto in the balance. The most painful thing was that we could all see it coming.
The former Malaga man started nervously for a man already armed with Champions League experience. Alongside Vincent Kompany, he gave the ball away under early pressure from the suffocating, relentless Catalans, but as City sat deep he remained safe with little in the way of space in behind.
Demichelis, whose lack of pace has already been exploited on more than one occasion this season, was always susceptible to the counterattack and unsurprisingly it was Messi who ruthlessly exploited that weakness.
To play the Argentine ahead of Joleon Lescott suggested that Pellegrini was playing it relatively safe. Sit, wait and break to devastating effect, rather than build from the back and to a point it had worked. Barcelona took over half an hour to get a shot away, but the feeling remained that the Blaugrana would eventually find a way through.
Pellegrini has no doubt been unlucky in losing Matija Nastasic to injury but it undoubtedly proved his squad's weakest position, with the eyes of the world watching on. Blame can't be totally apportioned to Demichelis, it was City's manager who simply left the grenade and hoped that Barcelona wouldn't pull the pin.
"They were there for the taking" was the party line come full time from captain Kompany. They knew this was an opportunity missed. This was no humiliation like the 3-1 defeat to Bayern Munich in October but now it matters so much more as City looks to take the next step in Europe.
City will travel to Barcelona next month down if not yet out, but the damage seems as close to irreversible as it gets, after Dani Alves' injury-time strike made it 2-0 and brought with it that shuddering sense of deja vu.