There are just a handful of matches still to play as Liverpool and Tottenham look to join Chelsea and Manchester City by punching their ticket to the Last 16.
But where they finish in their group also determines who they play at the start of the knock-outs, with teams that top their groups drawn against those who finish as runners-up, and clubs finishing third relegated to the Europa League.
So what does this mean for the British teams in this year's Champions League?
Liverpool
Liverpool were living in the depths of despair a month ago after their opening 4-1 hammering in Naples, but collecting nine points from their next three games – including a last-minute winner against Ajax and a spellbinding 7-1 win at Ibrox – has put the Reds in touching distance of qualification.
Avoid defeat against Ajax in Amsterdam on Wednesday and they qualify for the knock-outs. Should they win and Rangers collect points from Napoli on the same evening, all eyes will be on an effective play-off against Napoli in their final Group A match with top spot - and redemption - up for grabs. Anything less than two wins from two could see them finish as runners-up.
Finish 1st: Win against Ajax (A) and Napoli draw or lose to Rangers, win against Napoli (H)
Finish 2nd: A draw against either Ajax (A) or Napoli (H)
Rangers
Nothing short of a miracle will see Rangers climb above Ajax into the Europa League places, but stranger things have happened in football and in an alternative upside down world a win against table-toppers Napoli in Naples coupled with an Ajax defeat away to Liverpool could set them on their way to a historic showdown against the Eredivisie champions in Glasgow next Tuesday.
Finish 3rd: Win against Napoli (A), win against Ajax (H)
Tottenham
All outcomes are possible in Group D with just three points separating all four teams.
Table-toppers Tottenham host Sporting on Wednesday knowing a win will be enough to seal qualification ahead of a tricky trip to Marseille next Tuesday, but entertaining a team harbouring their own Champions League ambitions off the back of two straight league defeats will be no easy task.
Finish 1st: Win against Sporting Lisbon (H), win against Marseille (A)
Finish 2nd: Four points from two games will be enough to qualify, but lose against either Sporting Lisbon or Marseille, and Spurs could theoretically drop into the Europa League
Celtic
Celtic were already eliminated from the Champions League after a 2-0 defeat to RB Leipzig earlier this month, but are out of Europe altogether this season after a heartbreaking 1-1 draw at home to Shakhtar Donetsk on Tuesday that leaves them rooted to the foot of Group F.
They will bow out of the competition against Real Madrid at the Santiago Bernabéu next Wednesday, knowing that not even a historic win will be enough to lift them in to the Europa League.
Final position: 4th
Chelsea
The Blues qualified for the Last 16 with an impressive 2-1 win over RB Salzburg on Tuesday, a result that also meant they finished the evening as group winners.
Dinamo Zagreb's 4-0 defeat to AC Milan in the later kick-off renders their final match of Group E against Zagreb at Stamford Bridge next Wednesday as a mere formality, given their superior head-to-head record against AC Milan - the only team who could have caught them at the summit.
Final position: 1st
Manchester City
Manchester City had already qualified for the Last 16 long before any other British team as they waltzed through their opening fixtures, despite criticism of their performance against Copenhagen earlier this month.
Their 0-0 draw against Borussia Dortmund ensured City will enter the Last 16 as top seeds, regardless of their final result in Group G against Seville at the Etihad Stadium next Wednesday.
Final position: 1st
