Bayern Munich 5-1 Arsenal was a result that had two major repercussions. The first was that it established the German giants as the outright favourites to win this season's Champions League at 3.9, whereas they were previously sharing the status with holders Barcelona.
The other was that it eroded to rebuilt optimism which surrounded the Gunners' prospects of progress after prevailing 2-0 in the reverse fixture at the Emirates, instead elbowing the north Londoners out to 4.57/2 to reach the last 16 for the 16th successive campaign.
Arsenal and Dinamo Zagreb have three points to Bayern and Olympiakos' nine, with just six left to play for. In Arsene Wenger's words: "We have a chance to qualify. It's a small chance but a real one."
The size of the gap makes it seem daunting, though in reality they only need three results to fall in their favour. Firstly, they must beat Dinamo Zagreb at home on matchday five and hope that Bayern do likewise against Olympiakos. Both of these outcomes will trade at odds shorter than 1.25.
Then, more trickily, they need to triumph away to the Greek side, most likely by a two-goal margin to eliminate the head-to-head disadvantage incurred courtesy of their 3-2 loss in the Emirates clash. Their three prior visits ended in defeat, yet they didn't have this much at stake in any of those.
However, it is possible that Arsenal will be denied even if they pull out the two victories that they require because there is another factor at work: their reliance on Bayern bringing their best form into the upcoming collision with Olympiakos.
Pep Guardiola reassured that "Arsenal have to be calm and be sure that myself and the players are going to try to win" owing to the motive that "we want to be first in the group", but a draw will keep them on course for that target while also guaranteeing that both they and the Greeks qualify.
Bayern have plenty of previous for slacking off in the closing weeks of a group stage, albeit usually to the benefit of a Premier League team rather than the detriment.
You have to go back to 2009/10 - a bygone time in which Paris St-Germain finished 13th in Ligue 1 and Inter were the pride of Europe - to find the last time that they won on both matchday five and six, and back then they were rallying from a position of four points from four games.
In 2010/11, they surrendered a 100% record by losing at Roma. In 2011/12, they blew an unbeaten streak to Manchester City, ceding shots at perfection in 2013/14 and 2014/15 with defeats to the same adversaries, while in 2012/13, they were held by Valencia in their penultimate contest.
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