The Champions League returns after a three-week break as we reach the business end of the group stages.
Three of the four English teams – and several other European giants – could book a place in the knockout stages with two games to spare this week.
So who needs what to qualify and who can be eliminated?
Group E
Tuesday – Rennes v Chelsea, Krasnodar v Sevilla (both 17:55 GMT)
Chelsea could progress on Tuesday but they would need Sevilla to get at least a draw against Krasnodar.
If the Spanish side win in Russia, Chelsea will go through as long as they avoid defeat in France. If Chelsea win, they only need Sevilla to draw. If Krasnodar win, then Chelsea will have to wait.
Wins for Chelsea and Sevilla would send both through and eliminate Krasnodar and Rennes.
Group H
Tuesday – Manchester United v Istanbul Basaksehir, Paris St-Germain v RB Leipzig (both 20:00 GMT)
This is one of only two truly close groups.
Manchester United cannot clinch a place in the knockout stages this week. With placings determined by head-to-head record rather than goal difference, they could even end the day outside the top two if they lose to Basaksehir, as they did in Istanbul in the reverse fixture.
Group C
Wednesday – Olympiakos v Manchester City (17:55 GMT), Marseille v Porto (20:00 GMT)
Manchester City will progress to the last 16 if they pick up at least one point against Olympiakos in Athens on Wednesday.
Marseille will be eliminated if they lose at home to Porto.
Group D
Wednesday – Liverpool v Atalanta, Ajax v Midtjylland (both 20:00 GMT)
Liverpool will reach the knockout rounds if they beat Atalanta at Anfield. A draw will be enough if Ajax do not beat Midtjylland.
Danes Midtjylland will be eliminated if they lose.
Group G
Tuesday – Dynamo Kyiv v Barcelona, Juventus v Ferencvaros (both 20:00 GMT)
9 pts – Barcelona, 6 pts – Juventus, 1 pt – Dynamo Kyiv and Ferencvaros
Barcelona will progress if they win. Juventus will join them in the next round if they win, so long as Barcelona do not lose.
A draw would be enough for Barca if Juve do not lose.
Ferencvaros and Dynamo Kyiv need practically every result to go their way to qualify.
Group F
Tuesday – Borussia Dortmund v Club Bruges, Lazio v Zenit St Petersburg (both 20:00 GMT)
6 pts – Borussia Dortmund, 5 pts – Lazio, 4 pts – Club Bruges, 1 pt – Zenit St Petersburg
No teams can book a spot in the knockout stages, but Zenit St Petersburg could be out of contention if they lose and Borussia Dortmund win.
Group A
Wednesday – Atletico Madrid v Lokomotiv Moscow, Bayern Munich v Red Bull Salzburg (both 20:00 GMT)
9 pts – Bayern Munich, 4 pts – Atletico Madrid, 2 pts – Lokomotiv Moscow, 1 pt – Salzburg
Bayern Munich will be through to the knockout stages if they beat Red Bull Salzburg. They could afford to draw if Lokomotiv Moscow do not beat Atletico in the other game.
Group B
Wednesday – Borussia Monchengladbach v Shakhtar Donetsk (17:55 GMT), Inter Milan v Real Madrid (20:00 GMT)
5 pts – Borussia Monchengladbach, 4 pts – Shakhtar Donetsk and Real Madrid, 2 pts – Inter Milan
Nobody can seal their place in the last 16 or be eliminated in Group B.