A point will be enough in Leipzig next week, but suddenly that looks much easier written than achieved. A campaign that started so well has soured swiftly and while Manchester United still top Group H, little can be guaranteed from here.
They were beaten by the better team on Wednesday night, and already trailed when Fred was dismissed after 70 minutes. Indeed, given that he could have gone after 21 it could have been a lot worse.
Paris Saint-Germain were not flattered by the result and are close to a sure thing at home to Istanbul Basaksehir.
That leaves United needing to avoid defeat against RB Leipzig. If they do not, the Europa League beckons and the resulting mess it will make of the fixture calendar. It is not a disaster for United, yet; but it is teetering on the brink of it.
How did this happen? Having taking early control of a difficult group, how do United now stand one adverse result from elimination? Put simply: they lost in Istanbul.
With two dangerous opponents lurking, hay had to be made against the novices. The calamitous surrender in the away fixture would always leave them exposed if PSG got their act together – which they did.
PSG are a dangerous team and contrary results can always happen against them. This is the fourth straight time the away side has won in meetings between these teams. Yet Istanbul Basaksehir were there for the taking, and United lost. They have been vulnerable ever since.
As vulnerable as they looked for the winning goals here, the three key occasions when PSG were quicker to react in the six yard box. The French, certainly, were much improved on their earlier group meeting and scored the quickest goal of any Champions League visitors to Old Trafford since Wolfsburg more than five years ago.
There were just six minutes gone when a Kylian Mbappe shot was deflected into space on the right side of the penalty area.
United’s defenders were desperately slow to address the danger, meaning PSG were as good as queueing up to finish. Neymar, unsurprisingly, pulled rank on Moise Kean, but it was still a lovely shot from a tight angle.
Number two saw similar sluggishness curse United’s efforts. A Neymar corner, cleared, an Ander Herrera shot bouncing off Abdou Diallo and Marquinhos faster to the ball than any United defender, prodding it past David De Gea.
Injury time, victory was cemented, Rafinha making Harry Maguire appear very leaden-footed before cutting the ball back for Neymar to tap into an empty net. As if that was not bad enough, Marcus Rashford appeared to pick up an injury and went straight down the tunnel late on. United beat Leipzig 5-0 here earlier in the season. That seems an age ago now.
While Orsato was distracted by that, behind him Paredes collapsed and a gang of PSG players rushed towards the culprit, Fred. Neymar, a fellow Brazilian, diffused the situation but by then the VAR had suggested Orsato should inspect the footage.
Those at home who had seen it already suspected the outcome. Paredes came for Fred aggressively, the Manchester United man met fire with fire which, we presume, was exactly the reaction hoped for. Their heads met and Paredes then bounced backwards as if assaulted.
It was dispiriting to watch, but the blame in these circumstances invariably falls on the player sucked into reacting; and the punishment is consistent. Fred, red.
It was only when Orsato marched back holding a yellow card in his hand that anyone even contemplated a lesser sentence. Yellow it was. Maybe Orsato took into account Paredes’ part in it all. We could argue this was justice. It just wasn’t consistent with the reaction to incidents across world football. Ask Nicolas Pepe.
Yet if United were fortunate to be level, PSG could easily have been two down by the hour. Just four minutes into the second-half, a square pass from Rashford found Martial unmarked with the goal open. Somehow, he put it over.