Eleven teams will start the fourth set of Champions League group stage fixtures with a chance to seal a place in the round of 16 with two games to spare.
A look at the possible permutations ahead of this week's fixtures.
TUESDAY, OCT. 31
Group A: Manchester United (9 points) V Benfica (0 points), Basel (6 points) v CSKA Moscow (3 points)
- Man United will qualify on Tuesday if they win at home against Benfica and CSKA fail to beat Basel. United will also advance to the round of 16 if they draw and CSKA lose.
- Basel will advance with a win against CSKA if United avoid a defeat.
Group B: Paris St Germain (9) v Anderlecht (0), Celtic (3) v Bayern Munich (6)
- Paris will qualify if they win and Celtic fail to beat Bayern. PSG are also through if they draw and Celtic lose their match against the German Bundersliga champions.
- Bayern can secure a round of 16 spot with a win on Tuesday if PSG avoid defeat.
Group C: Roma (5) v Chelsea (7), Atletico Madrid (2) v Qarabag (1)
- Chelsea will qualify with a victory at Roma.
Group D: Olympiakos (0) v Barcelona (9), Sporting Lisbon (3) v Juventus (6)
- Barcelona will reach the last 16 if they win and Juventus avoid defeat at Sporting. The Spanish side will also qualify if they draw and Sporting lose.
- Juventus will secure a round of 16 spot with a win if Barcelona avoid a defeat.
WEDNESDAY, NOV. 1
Group E: Liverpool (5) v Maribor (1), Sevilla (4) v Spartak Moscow (5)
- Maribor will be out of the qualifying race if they lose and Spartak win on Wednesday.
Group F: Napoli (3) v Manchester City (9), Shakhtar Donetsk (6) v Feyenoord (0)
- Manchester City will qualify if they avoid defeat at Napoli on Wednesday.
Group G: Besiktas (9) v Monaco (1), Porto (3) v RB Leipzig (4)
- Besiktas are through to last 16 with a victory, or with a draw if Leipzig win at Porto.
Group H: Tottenham Hotspur (7) v Real Madrid (7), Borusssia Dortmund (1) v APOEL (1)
- The winner between Tottenham and Real Madrid at Wembley will guarantee qualification.