Probably the biggest talking point, certainly in English football, is Manchester City’s dangerous situation.
They sit 22nd after a 2-0 defeat at Juventus, only one point above the places that mean total elimination.
But much more than that, the team in that spot are Paris St-Germain, who City visit next on 22 January. PSG beat Red Bull Salzburg 3-0 to stay in the hunt.
The loser of that game next month will be on the brink.
Defending champions Real Madrid, even with their 3-2 win at Atalanta, are only one point above City and two above PSG.
Liverpool are the only team to win all their games – and be assured of a place in the knockout stages – after a 1-0 win over Girona.
Barcelona are next after a 3-2 victory at Borussia Dortmund, who sit ninth.
Arsenal and Aston Villa are both in the top eight after victories over Monaco and RB Leipzig respectively, along with Bayer Leverkusen, Inter Milan, Brest and Lille.
Brest, who beat PSV 1-0, are the biggest surprise of the tournament in their first season in any European competition. They have to play their home games in Guingamp because their stadium is not up to Uefa standards.
Dortmund, Bayern Munich, Atletico Madrid and AC Milan are the teams just below the top eight.
Celtic, who sit in between Real Madrid and City, drew 0-0 at Dinamo Zagreb and play point-less Young Boys next as they look to seal a play-off spot.
Leipzig, Slovan Bratislava and Young Boys have lost all six games.
A thrilling finale is sure on 29 January, when all 18 games will be played simultaneously at 20:00 GMT.
