Is there hope for Liverpool without Virgil van Dijk, is Axel Tuanzebe undroppable and are Manchester City's attacking talent malfunctioning?
Axel Tuanzebe's performance against PSG was phenomenal considering the last football match this man played came against Colchester in the EFL Cup 10 months ago. That day he marked Frank Nouble. In Paris, he was tasked with keeping Neymar and Kylian Mbappe at bay, arguably the two most dangerous forwards in world football.
Yes, they were perhaps a little below par of their usual standard but Tuanzebe looked like he had been bossing Champions League games his whole life. Filled with pace, power and excellent positioning, the defender twice stopped a full-flowing Mbappe from charging onto his goal with strong last-ditch defensive play.
Ole Gunnar Solskjaer now has a nice problem on his hands. United - as a defensive unit - looked supremely tight in a back three with Luke Shaw and Victor Lindelof equally as impressive. So, where does this leave skipper and £80m man Harry Maguire, who picked up a muscle injury at the weekend but is expected to be fit for Saturday's Premier League clash with Chelsea, live on Sky Sports?
Will Maguire - whose issues have been well publicised - struggle to get back in this team? Tuanzebe - surely - is un-droppable after putting Neymar and Mbappe in his pocket.
Sat Oct 24: Chelsea (h)
Wed Oct 28: RB Leipzig (h)
Sun Nov 1: Arsenal (h)
Wed Nov 4: Istanbul Basaksehir (a)
Sat Nov 7: Everton (a)
Tues Nov 24: Istanbul Basaksehir (h)
Sat Nov 28: Southampton (a)
Wed Dec 2: PSG (h)
Sat Dec 5: West Ham (a)
Tues Dec 8: RB Leipzig (a)
Sat Dec 12: Man City (h)
A win is always the most important thing in football. But in the circumstances, a clean sheet against a potent Ajax side wasn't far off for Liverpool on Wednesday night, with the pre-match bustle dominated by talk of Virgil van Dijk's long-term absence, and Jamie Carragher even questioning whether it will stop them from defending their Premier League crown.
Without their £75m man, Liverpool took some time to get to grips with Ajax's tricky front three, and had Adrian to thank for a first-half reflex save to deny Quincy Promes, before Fabinho went one better and cleared Dusan Tadic's chip off the line.
- Ajax 0-1 Liverpool - Match report and ratings
- How the teams lined up | Match stats
- Analysis: Fabinho's backline boost for Jurgen Klopp
But once they had settled, and with the experienced head of Jordan Henderson ahead of the untested combination of Fabinho and Joe Gomez, they looked as solid as they have done all season, something of little surprise to Klopp who said after the game his Brazilian midfielder is perfectly "comfortable" with his new position.
Let's not forget Van Dijk was present for all seven of the goals Liverpool conceded at Aston Villa before the international break, and while his world-class credentials should not be called into question, the Red wall has crumbled a little even with him in it ever since the restart in June.
If this was a test of whether Gomez and Fabinho can sit together as a competent, if never first-choice, backline pairing, the result was an encouraging pass after the latter's man-of-the-match performance, although these are of course early days.
The bigger issues more likely lie on the physio's table, which has already claimed Joel Matip - Liverpool's only other senior centre-back - this week. Perhaps only if injury should strike again, as is eminently possible in the congested era of coronavirus rescheduling, will Klopp be left scratching his head for their next solution.
Sat Oct 24: Sheff Utd (h)
Tues Oct 27: FC Midtjylland (h)
Sat Oct 31: West Ham (h)
Tues Nov 3: Atalanta (a)
Sat Nov 7: Man City (a)
Wed Nov 25: Atalanta (h)
Sat Nov 28: Brighton (a)
Tues Dec 1: Ajax (h)
Sat Dec 5: Wolves (h)
Wed Dec 9: FC Midtjylland (a)
Sat Dec 12: Fulham (a)
Manchester City beating Porto 3-1 looks on paper like one of those run of the mill nights for City in the Champions League.
But the scoreline didn't tell the whole story.
Pep Guardiola's men struggled for attacking fluency and had to rely on a penalty from Sergio Aguero and a moment of dead-ball brilliance from Ilkay Gundogan to keep Porto at bay. Apart from the attack that led to the penalty, City didn't manage a shot on Porto's goal in the first half.
And, their total of nine shots on goal was their lowest tally recorded in a Champions League home game under the watch of Guardiola. To give it some context, they managed 22 in their last-16 second leg against Real Madrid in the summer.
Perhaps the ruggedness of the Porto defence, led by Pepe, needs some praise in restricting Raheem Sterling and Aguero to so little space but the lack of rhythm in forward areas has become the norm so far this season. City's expected goals data is well down on the average of 2.34 in home matches in the Guardiola era - against Leicester it was 0.87 and despite beating Arsenal 1-0, a figure of 1.34 spoke volumes about how little they created.
It's back-to-back wins for City but improvement is still required.
Sat Oct 24: West Ham (a)
Tues Oct 27: Marseille (a)
Sat Oct 31: Sheff Utd (a)
Tues Nov 3: Olympiakos (h)
Sat Nov 7: Liverpool (h)
Wed Nov 25: Olympiakos (a)
Sat Nov 28: Burnley (h)
Tues Dec 1: Porto (a)
Sat Dec 5: Fulham (h)
Wed Dec 9: Marseille (a)
Sat Dec 12: Man Utd (a)
Successful teams have are usually built from the back. Chelsea flew in the face of that last season; conceding 54 Premier League goals, and 16 in eight Champions League games, but it did not stop them from reaching the last 16, and finishing fourth domestically.
However, after shipping nine goals in their opening five league games this season, winning only twice, something has clearly snapped. Chelsea kept a valuable clean sheet in Tuesday's Champions League-opening stalemate against Sevilla. But for all their talent and expenditure going forward, it came at the cost of creativity, managing only six shots all night and failing to test Yassine Bounou once.
- Chelsea 0-0 Sevilla - Match report and ratings
- How the teams lined up | Match stats
- Champions League fixtures | Group tables
- Watch Manchester United vs Chelsea live on Sky Sports
The game marked the Blues' first goalless draw under Frank Lampard since he took over nearly 18 months ago. That is no coincidence; he has rarely, if ever, prioritised his defenders' clean-sheet bonus over paying out for his attacking talent to get among the goals.
But after throwing away a 2-0 and 3-2 lead against Southampton on Saturday - the second time Chelsea have conceded three goals in a game already this season - no wonder he called the stalemate a "positive result" and admitted a clean sheet was a "big deal" for the club.
The problem is finding a balance. And it has been a delicate act for Lampard ever since an attacking-minded and potent Chelsea played well but were clinically thumped 4-0 by Manchester United in his first game as manager.
And it certainly eluded a Blues side whose best effort came from Kurt Zouma's header from a corner on Tuesday night. Not Christian Pulisic, Timo Werner or Kai Havertz, a trio who cost the Blues in excess of £150m to add to their forward ranks, but barely had a sight of goal between them.
There are certainly positives to be taken from an unusually stout defensive performance against a bunch of wily visitors in Sevilla.
But while Chelsea must improve at the back, they cannot afford to lose their best asset, their potency with the ball, as the trade-off. Can they manage both with the squad at their disposal? It's early days, but far from guaranteed.
Sat Oct 24: Man Utd (a)
Wed Oct 28: FK Krasnodar (a)
Sat Oct 31: Burnley (a)
Wed Nov 4: Rennes (h)
Sat Nov 7: Sheff Utd (h)
Tues Nov 24: Rennes (a)
Sat Nov 28: Tottenham (h)
Wed Dec 2: Sevilla (a)
Sat Dec 5: Leeds (h)
Tues Dec 8: FK Krasnodar (h)
Sat Dec 12: Everton (a)