The Champions League group stage has now reached the business end, with just two games remaining for Europe's big guns to seal a place in the knockouts.
Four teams have already confirmed their spots in the last-16 in Liverpool, Bayern Munich, Juventus and Ajax. But for a number of high-profile sides, there's still a lot of work to do.
Last year it was Chelsea and Manchester City who contested an all-English final, with Kai Havertz giving the former a slender 1-0 victory.
Thomas Tuchel's side, who sit top of the Premier League table after 12 games, can secure their place in the last-16 against Juventus on Tuesday night, while Pep Guardiola goes head-to-head against potentially Premier League-bound Mauricio Pochettino once more on Wednesday.
Meanwhile, Michael Carrick will lead Manchester United into their season-defining crunch fixtures after Ole Gunnar Solskjaer's reign came to an end, and he can seal qualification with a victory on Tuesday.
With just two rounds of fixtures remaining in this year's Champions League group stage, Sportsmail takes you through the state of play.
Group A
Anything but progression to the last-16 for Manchester City would be a total shock, though Guardiola would tell you there's work still to be done.
They come up against PSG on Wednesday night, needing just a point in their final two outings to officially qualify for the knockouts.
That's because, even with two victories, Club Brugge would only be able to level points with the Premier League champions, with head-to-head record then coming into play. City beat the Belgians 5-1 and 4-1 earlier in the campaign.
PSG would secure their spot in the knockout stages with either two draws, coming up against Club Brugge in their final outing, or by winning either of their final fixtures.
Meanwhile, both City and PSG will qualify, regardless of their result, should Club Brugge fail to beat RB Leipzig on Wednesday.
The Belgians need two victories to stand any chance of qualification, while RB Leipzig are sat on just one point and are already out.
Remaining fixtures:
Group B
Group B is set for an enticing finale, with three teams of huge historical significance still fighting for a runner-up spot.
Liverpool have already secured the title of group winner, however, and will be seeded going into the round of 16 draw. Jurgen Klopp's side have won all four of their matches to date and can safely rotate as they focus on the Premier League.
Though the battle for second place is intensely close, Porto can secure their progression with an away win at Liverpool on Wednesday, so long as third-placed Atletico Madrid lose to AC Milan.
Four points would ultimately be enough for the Portuguese outfit.
Spanish giants Atletico know they must avoid defeat at home to Milan on Wednesday to keep qualification in their own hands, with a final-day win away at Porto then enough.
Meanwhile, AC Milan know that qualification is only possible with two wins. A loss against Atletico on Wednesday would see even third place - and therefore a Europa League spot - move out of sight.
Remaining fixtures:
Group C
Similarly to Liverpool, Ajax can also relax after securing their place in the knockouts in the first four group stage games.
The Dutch side conceded just two goals as they largely strolled to four wins from four, including a 7-1 aggregate thrashing of Borussia Dortmund in their two clashes.
Dortmund are in a battle for a runner-up spot, though after defeating Sporting CP 1-0 in their home clash, another win in Wednesday's reverse fixture would see them progress to the knockouts by virtue of head-to-head record.
A draw would see it go down to the final day, but the German outfit would still have a better head-to-head record, meaning any win against bottom side Besiktas would do.
However, Sporting could also secure their knockout place on Wednesday night should they beat Dortmund by two goals.
Having lost all four of their matches to date, Besiktas' Champions League hopes are already gone. However, an unlikely two wins from two could see them finish third and thus drop into the Europa League.
Remaining fixtures:
Group D
Real Madrid are in a strong position to qualify for the Champions League knockouts, despite their shock defeat to Sheriff back in September.
Los Blancos have won three of their four games to date and can seal a last-16 spot with victory over Sheriff on Wednesday.
A loss could see Carlo Ancelotti's side drop to third in the table with just one game remaining, however, with the Moldovan outfit moving ahead via head-to-head record.
Having already beaten Inter Milan, two draws would be enough for Madrid, who finish their group stages against the Italian giants.
Inter can also qualify with a game to spare on Wednesday, proving they beat Shakhtar Donetsk and Madrid avoid defeat to Sheriff.
Shakhtar still have slim hopes of a Europa League place at least.
Remaining fixtures:
Group E
Bayern Munich have comfortably made the knockouts once more, scoring a whopping 17 goals in their four victories to date.
They need a point to officially confirm top spot in Group E, though even if they were to lose both games, Barcelona would have to beat the German giants by four goals to leapfrog them into first place. A seeded place almost certainly awaits.
All eyes are on Barcelona, with Xavi now confirmed as Ronald Koeman's successor. The legendary midfielder won his first game in charge, beating Real Sociedad 1-0 over the weekend, but now a crunch Champions League affair awaits.
The Catalan side face third-placed Benfica on Tuesday, knowing a win will take them through to the knockouts. It would put them on nine points and out of reach for the Portuguese side, currently on four.
However, in finishing their group away at Bayern, while Benfica will play at home to bottom side Dynamo Kyiv, they will desperately want to wrap it up at the Nou Camp on Tuesday.
For Benfica, a pair of historic wins in their final two outings would see them progress to the last-16.
Meanwhile, a Europa League spot is the most likely aim for Dynamo Kyiv, though mathematically a last-16 place is still possible.
Remaining fixtures:
Group F
The table suggests Manchester United are in a genuine battle for a Champions League knockout place - and so they are. However, their task ahead, although not easy, is simple. Beat Villarreal on Tuesday and qualify for the knockouts.
Again, it's head-to-head record, rather than goal difference, that determines who progresses if two sides are on equal points, meaning Cristiano Ronaldo's 95th-minute winner at home to Villarreal could now prove crucial.
United can take comfort knowing their final game is at home to bottom side Young Boys, while Villarreal travel to Atalanta. However, they did lose to the Swiss side in the reverse fixture.
Meanwhile, similarly to United, Villarreal can also confirm their qualification on Tuesday night, so long as they beat the Manchester club either 1-0 or by more than two goals.
Should that be the case, United could find themselves in third place come the end of the evening, providing Atalanta beat Young Boys. The Italians simply need two wins to guarantee qualification, though four could be enough should United beat Villarreal.
Young Boys next face a decisive game against Atalanta: win and even a top-two place remains possible; lose and even a Europa League spot is out of the question.
Remaining fixtures:
Group G
Group G is one of the more open of the eight, with just four points separating RB Salzburg in first and Sevilla, who are surprisingly in fourth having failed to win any of their games.
Plenty of twists and turns are expected yet, however, with Salzburg and Lille going head-to-head on Tuesday night, while Sevilla - who could be second by the end of the night - host Wolfsburg.
Sat two points ahead of Tuesday's opponents Lille, Salzburg could guarantee qualification with a victory. They would also take top-spot should Wolfsburg fail to beat Sevilla away.
Neither Lille or Wolfsburg can secure qualification on Tuesday but both can both move into the top-two with victories, before they go head-to-head in the final fixture.
Sevilla still have it all to play for, but a loss on Tuesday would see them drop out of the Champions League.
Remaining fixtures:
Group H
Qualification for the Champions League last-16 is already all-but decided in Group H, with Juventus through and Chelsea on the verge.
Juventus have been dominant throughout, conceding just two goals in their four impressive victories to date.
The Italian outfit can claim top spot with a point at Stamford Bridge on Tuesday, which would ensure them a better head-to-head record.
Meanwhile, Chelsea need just a point to officially progress to the knockouts, but a victory of more than one goal would also see them leapfrog Juventus going into the final game.
Zenit St. Petersburg can still qualify for the knockouts, mathematically anyway. They need to win their remaining two games, including against Chelsea, where they would need to win by at least two goals. Chelsea would also have to lose to Juventus. It seems a Europa League place is more likely.
Meanwhile, Malmo have no chance of qualification for the knockouts, but the Europa League remains a possibility.
When is the Champions League last-16 draw?
The draw for the 2021/22 Champions League round of 16 will take place on December 13.
It will be held at the House of European Football in Nyon, Switzerland and will get underway at 11am in the UK.
The draw will consist of the eight group winners and thus seeded teams and the eight runners-up. The seeded side will play away in the first leg.
No teams from the same nation can be drawn against each other at this stage of the competition.