The Old Trafford club were toiling under the dour negativity of Jose Mourinho, the Parc des Princes side were flourishing, winning regularly and scoring freely.
Barely two months on, though, and the tables are turned.
Under Ole Gunnar Solskjaer, United have rediscovered their customary swagger, while this clash could not have come at a worse time for PSG.
Not only have they hit a rocky patch of form, they also face the journey to Old Trafford with a squad that suddenly looks threadbare.
While there is a strong argument that a team with the resources of PSG should not find themselves in such a patchwork state – one that even head coach Thomas Tuchel would doubtless subscribe to – the stark reality is that as they prepare to face Solskjaer’s outfit is that they suddenly look short on quality.
Luck has played its role, deserting the Parc des Princes club at a vital juncture. Neymar, the game’s most expensive player, has suffered a reoccurrence of a foot injury, while Edinson Cavani is sidelined with a thigh problem sustained in the process of scoring the only goal of his side’s 1-0 win over Bordeaux at the weekend.
Both are certainly out of the trip in midweek and very probably the return in Paris next month.
“It’s too much,” Tuchel lamented to Canal+ after watching his side struggle to three more points on Saturday. “These are quality players who are here for the decisive matches in the Champions League, to play at the best level. It’s not possible to lose all of the players capable of fighting at this standard.
“We don’t have a backup to Edi, we don’t have a backup to Neymar.
“We’re no longer looking at Plan B but Plan D.”
Although Kylian Mbappe is available, PSG’s lack of offensive depth is belied by the fact that Eric-Maxim Choupo Moting, a man with only one goal in 595 minutes on the field, is the only other natural option at centre-forward for the next month.
Meanwhile, Timothy Weah, who has twice the goals in around quarter of the time, was shipped out on loan to Scottish champions Celtic just a couple of weeks ago.
But while the headline issues are at the vanguard of the team, there are concerns that are just as chronic in the heart of the field.
Marco Verratti seems to have won his race against time and an ankle problem to be fit for this clash, though after just an hour at the weekend, there is no doubt that he will be lacking the sharpness required to be at his absolute best.
Alongside him in the midfield, it promises to be a lottery as to who plays.
Adrien Rabiot is back training with the squad after being frozen out due to his ongoing contract dispute but has not played since early December and was not even among the substitutes at the weekend, while Leandro Paredes has played barely two hours of football with his new team-mates, virtually all of which came against third-tier opponents.
Dani Alves has been used as a central midfielder of late, but the likelihood is that he is asked to feature in his natural right-back role due to a concussion suffered by Thomas Meunier at the weekend.
Marquinhos, a centre-back by trade, is the man perhaps likeliest to feature.
Though constrained by the bonds of Financial Fair Play, PSG have been plunged into this ill-timed crisis by transfer window mismanagement. The lack of depth in attack and midfield are issues that have not been properly addressed in two transfer periods and it is little wonder that Tuchel is publicly at odds with sporting director Antero Henrique.
“You must ask Antero!” Tuchel responded after being asked why PSG had only one midfielder available for their first Champions League clash of the season, when their failure to sign a midfielder in August was still an open wound.
That match had ended in a 3-2 loss to Liverpool at Anfield, in which the French champions had given a performance so poor that they were flattered by such a narrow reverse. Only the quality of Neymar and Mbappe had saved from a true embarrassment.
History could just as easily repeat itself on Tuesday, when they are back in England against opponents suddenly resurgent. This time, though, they are without two-thirds of their star offensive trio to dig them out.
Indeed, there is already a sense of déjà vu heading into this tie, as it was around this time last year that Neymar suffered his initial metatarsal injury, keeping him out of the home second leg of a last-16 time against Real Madrid that was not yet decided.
But while the loss of such a player cannot be accounted for, it can be mitigated, and over an extended period, PSG have failed to take adequate precautions. The repercussions, however, may well be severe: another early European exit looms.