Yahoo Sports State of play in Champions League & how next phase works
Manchester City are in danger of Champions League elimination, Liverpool are flying while Arsenal and Aston Villa are in good shape.
Celtic's play-off hopes, meanwhile, are alive as the 36-team league phase of the revamped Champions League approaches its climax.
The top eight automatically progress to the last 16 and, crucially, skip the two-legged knockout play-off round.
City, the 2023 winners, are far from the only heavyweights sitting uncomfortably.
Who qualifies for the knockout phase?
First, here's a reminder of what the 36 league-phase teams are aiming for.
Those finishing in the top eight automatically progress to the last 16, where they will be seeded.
They will await the winners of eight two-legged knockout play-off ties featuring the clubs ranked from ninth to 24th.
Those finishing between ninth and 16th will be seeded and face a team placed 17th to 24th, with the advantage of playing the second leg at home.
The clubs 25th or lower are eliminated and do not gain entry to the Europa League.
Which teams have qualified?
Liverpool and Barcelona became the first teams to qualify for the knockout stage on Tuesday night with a game to spare.
Arne Slot's side beat French club Lille at Anfield to maintain their 100% record in the competition this season.
The result means the Reds are guaranteed a top-two finish and therefore a top seeding place in the knockout draw.
Barcelona's 5-4 win against Benfica means the Spanish club are also guaranteed a finish in the top-eight, although they could slip further down the table depending on other results in Wednesday's games and next week's.
What about Arsenal, Aston Villa, Man City and Celtic?
Arsenal and Villa are both guaranteed places in at least the play-offs but they will be hoping to go straight through to the last 16 by finishing in the top eight.
The Gunners have two matches left, starting with Wednesday's home game against Dinamo Zagreb. Depending on other results, a victory could confirm a top-eight finish for Mikel Arteta's side.
Villa's chances were dented by a 1-0 defeat to Monaco on Tuesday, but they remain in the top eight before their final league-stage fixture against Celtic.
Celtic are 23rd in the table - two places above the elimination places.
Brendan Rodgers' side take on Young Boys - who are bottom of the table and without a point in the Champions League this term - at Celtic Park on Wednesday.
A win would almost certainly guarantee Celtic a knockout play-off spot.
Manchester City are a place and a point behind Celtic in 24th.
Pep Guardiola's side face a daunting trip to Paris St-Germain on Wednesday before a home tie against Club Brugge on matchday eight.
A win against PSG would significantly boost City's chances of a knockout play-off spot but it would not guarantee it.
A thrilling finale is assured on 29 January when all 18 final group games will be played simultaneously at 20:00 GMT.
Does it matter where you finish in top eight?
Definitely.
Where a team finishes in the league table determines which opponents they face and when they can face them in the knockout stages.
Take Liverpool for example. The Reds are now guaranteed a top-two finish, which gives them a seeded route through to the last 16.
That means the Reds will face a team who finished 15th, 16th, 17th or 18th in the last 16 and they cannot face the team who finishes second - currently Barcelona - until the latter rounds.
By contrast, a team that finishes seventh or eighth will face one of the eight teams that comes through the play-offs. That could be a side that had finished just below them in the league phase - in ninth or 10th.
What's the difference between finishing 9th and 24th?
This definitely matters.
Teams finishing between ninth and 24th will face each other in a play-off round to determine who reaches the last-16.
There is no play-off 'draw' as such - it is determined by where a club finishes.
The team in ninth - the best performing team outside the top eight - take on the team in 24th - the worst performing team outside the top eight.
And so on. So 10th faces 23rd, 11th plays 22nd, 12th take on 21st. You get the idea.
In theory, your reward for finishing ninth is to face the worst-performing team above the elimination zone.
That said, as things stand that would mean French club Brest - who are ninth - face Premier League champions Manchester City, who are 24th.
How many points are needed to qualify?
Given this is the first edition of the new format, it remains to be seen exactly how many points will be required to achieve a top-eight finish, or avoid elimination from the competition.
Before this season's competition, Opta calculated each team's projected points tallies and likelihood of progressing based on 50,000 simulations of the league phase.
They found that 16 points - potentially five wins and one draw from eight matches - would give a 98% chance of finishing in the top eight.
After gameweek five, Opta recalculated and said 16 points would now give teams an 87% chance of a top-eight finish.
Meanwhile, achieving 10 points - three wins and one draw, for example - would give teams a 94% chance of securing a place in the top 24.
However, any team collecting fewer than eight points can expect their involvement in European competition this season to come to an end.
Watch highlights of every Champions League game from 22:00 on Wednesday on BBC iPlayer and the BBC Sport website and app.
There will also be a Champions League Match of the Day on BBC One on Wednesday, from 22:40 to 00:00.
