Three things to look out for this week:
1. When Liverpool beat Paris on matchday one, they appeared well set for qualification, particularly as Napoli were held at Crvena zvezda.
How the tables have turned. The Reds have lost to every other team in the group since and now sit three points behind the Italians and two adrift of Paris.
Carlo Ancelotti is arguably the last coach they would want to face in their decider too. The 59-year-old oversaw home and away wins - and two clean sheets - against Liverpool in his first season (2009/10) as Chelsea coach.
Ominously for the Merseysiders, his maiden campaign at Napoli has already featured a 1-0 win against them.
But James Milner insists Liverpool do not deserve to be in the Champions League if they are unable to beat Napoli at Anfield.
The Reds are at risk of being eliminated from the competition after losing 2-1 to Paris Saint-Germain last time out.
Jurgen Klopp's side must beat Napoli 1-0 or by two clear goals in their final Group C match to progress to the knockout rounds and Milner has called on his teammates to get the job done at Anfield.
"We know it was a tough group all along, the Champions League is tough," said Milner. "But to have it in your own hands going into the last game and having a home game ... I don't think you can ask for more.
"If you had said 'you have to win your last home game to get through the group' I think everyone would have been fine with it.
"If you can't win your home games in the Champions League then you don't deserve to go through. I'm not concerned, we've played pretty well this season."
Liverpool will drop into the Europa League if they fail to beat Napoli.
2. If it's a head-to-head shootout you're looking for, then Shakhtar versus Lyon is the game for you. The Ukrainian side have to win to progress, which could play into the attack-minded French outfit's hands.
Bruno Génésio's side have scored twice or more in every group game and could become the sixth side to do so in all six matches if they repeat the feat at the OSK Metalist Stadion. The five teams who achieved that sequence previously - Tottenham, Bayern, Barcelona and Real Madrid (twice) - all progressed.
3. Talking of Barcelona and Tottenham, they meet at the Camp Nou with the visitors needing to equal Inter's result to guarantee their last-16 spot alongside the hosts.
Beating the Catalan club would be particularly sweet for Mauricio Pochettino, a former player and coach at Barça's city rivals Espanyol.
The Argentinian earned his first win as a manager in a derby at the Camp Nou in 2009. "Espanyol were bottom and Barcelona were top," he recalls. "All the people were saying Espanyol were dead and had no chance. It was a special victory and an unbelievable memory." Could lightning strike twice?..