Season-defining games come earlier and earlier in campaigns but it is no exaggeration to claim that when the Champions League resumes on Tuesday the meeting between Paris St-Germain and Chelsea at the Parc de Princes will be momentous.
Neither club can contemplate exiting the competition at this stage - the last 16 - such is their ambition and expectation. It will be a difficult one to explain away, whatever happens in the matches.
Along with Manchester City's tie against Barcelona, it feels not just the pick of the round but a meeting that could have far-reaching consequences for some of those involved; the kind of result that can lead to a reckoning. Specifically for the managers.
For the PSG coach, Laurent Blanc, in particular, it may decide whether he remains beyond this season. But do not underestimate, either, the importance of "the trophy with the big ears" to Jose Mourinho, who now has not won it since 2010. That is starting to feel like a long time for such a serial achiever.
There is no suggestion that his future at Chelsea is in any doubt but he needs to back that faith with trophies this season. The Premier League title may be enough - but going out of the Champions League at this stage would be a big stain.
Blanc has the air of a man who knows his employer, Qatar Sports Investments, is always looking over his shoulder to see who may be on the horizon.
He was never their first choice to succeed Carlo Ancelotti as coach and there was an element of surprise that his contract was renewed last summer. That deal runs out in 2016 - after one year was added to extend his contract - but the Qataris would not hesitate to pull the trigger before then should Blanc falter.
Winning the French title is a given for whoever is coach of such a fabulously wealthy, well-resourced, dominant club - although PSG have a fight on their hands with Lyon and Marseille to this season - and progressing in the Champions League is a must.
It is not too far-fetched to consider that Michael Laudrup has been 'parked' as coach with the Qatar club Lekhwiya for a season to see whether or not he should succeed Blanc. Laudrup ruled himself out of taking over from Harry Redknapp at Queens Park Rangers probably because the Dane knows that he may have bigger and far more lucrative options.
There will probably be jibes between the two managers in the pre-match press conferences tomorrow, while there will also be a great deal of interest in David Luiz, who PSG are planning to make available to the media.
The Brazilian's extraordinary pounds 48?million move from Chelsea to PSG last summer - a world record for a defender and at least a third more than the French club originally intended to pay - is another sideshow to the encounter. Or should that be a Sideshow Bob to the encounter?
The timing, at the end of the week, of Chelsea finally announcing that Eden Hazard had signed a new contract was probably also not coincidental, given the established interest PSG hold in the Belgian international.
Mourinho will poke Blanc over Financial Fair Play, undoubtedly, and over the lack of domestic competition PSG face. The Chelsea manager may also remind the world that he has turned down PSG twice - the second time before Blanc was appointed - although the French club remain a likely destination when he eventually leaves Stamford Bridge.
Blanc has got his retaliation in first - by joking, albeit with a hard edge, that Mourinho is a "genius" for losing the FA Cup tie against Bradford City because it meant his players could have a weekend's rest.
"They lost the FA Cup game against Bradford 4-2, which gave them a week to prepare for the Champions League game against us," Blanc said, before pointedly adding: "Just think about the tsunami of criticism there would have been if PSG had lost a game like that. People would have said PSG's coach does not understand anything. It's like that."
There will be a 'tsunami' should PSG be badly beaten by Chelsea having, of course, gone out in the quarter-finals last season to the same opponents, albeit on the away-goals rule. PSG won 3-1 at home last season but then lost 2-0 at Stamford Bridge - with Hazard's penalty in Paris proving decisive. Also decisive was Zlatan Ibrahimovic's absence from the second leg, through injury, and Edinson Cavani's profligacy in front of goal, as well as Blanc's tactical limitations on the night.
Both Chelsea goals at home were scored by players no longer at the club - Demba Ba and Andre Schurrle - but the west London club are undoubtedly far stronger this season, as Luiz has already graciously acknowledged, with the additions of Thibaut Courtois, Filipe Luis, Cesc Fabregas, Juan Cuadrado, who is eligible having only played in the Europa League this season for Fiorentina, and, of course, Diego Costa.
The striker will eagerly return to the starting line-up, having been ruled out for three games after his alleged 'stamp' on Emre Can.
In truth, Chelsea have not played consistently well for weeks. The demolition of Swansea City away was a rare convincing display. They could do with another strong performance now.
PSG are not stronger. They are unbeaten at home this season after 16 matches in all competitions but their big names have struggled for form and fitness - although there are signs of improvement since the winter break.
One concern will be the fitness of Ibrahimovic, who has been enduring a virus. Although the striker is expected to play, Blanc claimed that the player had been "bombarded with anti?inflammatories and antibiotics".
PSG undoubtedly need him - and need him to be at his best - if they are to succeed. Their home record in Europe is formidable - unbeaten in 32 matches since they lost against Hapoel Tel Aviv in 2006-07 in the Uefa Cup - but Chelsea do not need to win on Tuesday to go through, as they proved last season. They will be expected to go through again this time round.