Newcastle United manager Eddie Howe billed his side's upcoming Champions League group game against Paris Saint-Germain as a "defining moment" in the season. The Magpies are far from the only club facing a decisive week of European football.
With just two rounds of Europe's premier club competition left to play, only six clubs have no chance of making it into the lucrative knockout stages. The same number have qualified for the round of 16, leaving 20 clubs in limbo with just 180 minutes of Champions League football to contest before Christmas.
Here's every club on the cusp of elimination this midweek.
Every club that cannot qualify for the 2023/24 Champions League knockout stages
While Real Madrid broke the world transfer record twice in a matter of days by signing Kaka (£60m) and Cristiano Ronaldo (£80m) in 2008, Union Berlin's fans volunteered on the construction site of a new stadium to save the club £1.7m. Union made their Champions League debut at Madrid's home ground in September and were only denied a deserved point by Jude Bellingham's 94th-minute winner.
That loss was the third in a sequence of 12 consecutive defeats across all competitions for the German upstarts. Even though Union ended that run with a 1-1 draw at the home of Italian champions Napoli last time out, their Champions League dream is over.
Fellow debutants Antwerp are also out after losing all four games in the competition, despite taking the lead at home to Shakhtar Donetsk and Porto.
RB Salzburg, Benfica, Red Star and Young Boys fell victim to getting drawn in groups with two clear favourites to qualify automatically. While beaten finalists Inter have been matched stride-for-stride by Real Sociedad in Group D, reigning champions Manchester City and RB Leipzig have dominated Group G.
Who can be eliminated from the Champions League on Matchday 5?
Group A - Man Utd
Manchester United were infamously greeted with a banner welcoming them to Hell for their first-ever encounter with Galatasaray in Turkey. Defeat on Wednesday night for Erik ten Hag's sight would consign them to the elite footballing equivalent of the underworld, the Europa League, as a best-case scenario.
Even a draw for United in Istanbul would not be enough if Copenhagen were to pull an upset and defeat Bayern Munich away from home on the same night. While a slip-up from the Bavarians is unlikely, Thomas Tuchel may rest key players with Bayern already assured of first place in Group A.
Remaining Group A fixtures
Group B - Lens & Sevilla
Arsenal are not yet qualified but will remain top of Group B even in defeat this week. The jeopardy in this section lingers over Lens and Sevilla.
Lens travel to the Emirates on Wednesday night knowing that a loss would see their chances of qualification for the knockouts extinguished if PSV Eindhoven are also able to defeat Sevilla. If the Spanish side were to lose at home to PSV, they would be out.
Sevilla wouldn't even have their precious Europa League to fall back on if they lose to PSV and Lens get a victory at the Emirates.
Remaining Group B fixtures
Group C - Braga
The future of Real Madrid (qualified) and Union Berlin (eliminated) at either end of the group is confirmed. Napoli's fate is very much in their own hands while Braga have to hope that the Spanish giants do them a favour this week.
If Napoli defeat Real Madrid at the Bernabeu - a feat the club has never achieved - Braga are out. However, if the Portuguese side, who are at home to winless Union, were to better Napoli's result on matchday five, they could take qualification to the final day, which is an intriguing trip to Naples.
Remaining Group C fixtures
Group E - Feyenoord & Celtic
Somehow, Celtic still have a chance of qualifying for the knockout stages with one point from four games. The Scottish champions not only have to win their remaining matches (away to Lazio before Feyenoord's visit) but must also rely upon Atletico Madrid taking at least four points from their last two games.
Feyenoord would be instantly thrust into the Europa League on Wednesday if they lose at home to Atletico and Lazio defeat Celtic at the Stadio Olimpico.
Remaining Group E fixtures
Group F - AC Milan & Newcastle
Howe had clearly been pouring over the permutations ahead of Newcastle's trip to Paris on Tuesday. "It is imperative we don't lose," he quite rightly declared. Defeat would eliminate the Magpies but they are not the only Group F outfit at risk this week.
AC Milan would also be denied a spot in the knockouts if they lose at home to table-topping Borussia Dortmund and PSG beat Newcastle.
Group F remaining fixtures
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This article was originally published on 90min as Champions League group stages: Who can be eliminated on Matchday 5?.