In Bergamo on Tuesday night the narrative was that Cristiano Ronaldo had rescued Ole Gunnar Solskjaer again, but for the Norwegian's long-term prospects at Manchester United, it was something that happened well before Ronaldo's rescue act that might have a more damaging impact.
Seeing Raphael Varane go down under no pressure and immediately call for treatment, Solskjaer must have realised how seismic a blow this was to him at United. There's a strong argument to say it would have been preferable to lose Ronaldo. At least there's a ready-made and in-form replacement in Edinson Cavani.
For Varane, there is no such luxury. He'd missed three games for United with a groin injury before returning at Tottenham and those three matches had seen 11 goals go in against them. Back at Spurs and holding the defence together at the centre of a back three, United produced their most assured defensive performance of the season in keeping a clean sheet in a 3-0 win.
That success bought Solskjaer time after a week where he only just survived. The draw against Atalanta wasn't disastrous, even if the performance left a lot to be desired, but it still feels like the United manager is in the kind of territory where he's surviving from game to game, week to week.
United might remain adamant they're backing their man, but the 5-0 defeat to Liverpool at Old Trafford will linger in memories for a long time at board level. Another defeat as bad as that could spell the end.
So to lose Varane ahead of Saturday's derby with Manchester City could yet be the most costly injury to Solskjaer in his near three years in the job. It changes so much in regards to how United play and Solskjaer's options.
When the teamsheet landed in Bergamo it was no surprise the Norwegian had stuck with a back three. It worked well at Tottenham, where United were hugely improved defensively, were much more compact and played with more control than they had at any point in the season.
The start against Atalanta had been tougher and United were behind when Varane went off, but they hadn't given away many chances and they would have been level but for a David de Gea blunder. Having lost Victor Lindelof to a training ground injury on Monday, Varane's withdrawal signalled Solskjaer reverting to a back four, with Harry Maguire and Eric Bailly at centre back.
From there on in Maguire was flustered and he remains worryingly short of the form he showed in the second half of last season and for England at Euro 2020, while Bailly was all-action as usual.
With Varane now out for a month, Solskjaer will be sweating on Lindelof's fitness for the derby, but without the France international there may already be a reluctance to continue with the back three.
The 28-year-old was excellent in leading the defensive line at the Spurs' Stadium, communicating with those around him superbly. Solskjaer values the partnership between Maguire and Luke Shaw on the left, so it would need Lindelof and Bailly to be fit to start to play three at the back, unless Shaw drops back to be the left-sided centre back.
That would mean Maguire playing the most important role in the middle of a back three, something that would be demanding given his current slump in form. Beyond Maguire, Bailly and Lindelof if he's fit, the next cab off the rank at centre back is Phil Jones.
If Solskjaer decides the back three won't function without Varane then he will be forced back into the 4-2-3-1, a system United have struggled in this season and which could be particularly risky against City.
It was that shape that led to the catastrophic defeats to Leicester City and Liverpool, when United shipped nine goals and were cut to ribbons time and again.
In that system this season United have been too open, with the gaps between midfield and attack and midfield and defence like the Grand Canyon. Both Leicester and Liverpool found it easy to play around United's overworked midfield and put pressure on a creaking defence.
It feels instructive now to remember what Brendan Rodgers said after his side's 4-2 win at the King Power Stadium. "T heir central players weren’t pressing so we could be patient and work the ball through the pitch, we got into some really good areas and put pressure on their backline," he said.
It all sounds so simple, but it also sounds like exactly the kind of approach City take under Pep Guardiola. If Varane's absence forces Solskjaer into the 4-2-3-1 and those fundamental issues haven't been fixed, then it could be ideal for a patient and probing City.
That's why Varane's injury could be the biggest blow yet to Solskjaer in his time at United. The task on derby day has got considerably tougher without him.
