Galatasaray v Juventus - Group B, Sky Sports 4 HD (19:30), Sky Sports 4 (Tuesday, 19:30)
Given Juventus' struggles early in the group (two points from their first round of three games) and the utter dominance of Cristiano Ronaldo and Real Madrid, this game always looked likely to be a winner-takes-all affair, and it has proved thus.
Juve may be back on top of the pile in Italy after seven consecutive victories (ridiculously all without conceding a single goal), but their task in Istanbul is not an easy one. Other than the 6-1 defeat to Real Madrid in September, Gala are unbeaten at home since March, winning 15 of their 18 matches in that period at the Ataturk Stadium.
It is difficult to overstate the intimidating atmosphere that will await Juve in Turkey. Smoke bombs, flares, projectiles and abuse are all par for the course, and when you factor in the magnitude of the fixture, it would be a courageous and impressive performance by Antonio Conte's side to avoid defeat. If Gala score a late winner, you'll feel the windows shake in Ilkley and Ipswich, let alone Istanbul.
Schalke v Basel - Group E, Sky Sports 4 - Red Button (Wednesday,19:45)
Basel's Champions League campaign so far has been completely backward. Taking six points off Chelsea should have seen the Swiss side qualify for the knock-out stage already, but they have somehow managed to garner only another two points from games against Steaua (home and away) and Schalke (home). Murat Yakin's side travel to Gelsenkirchen knowing exactly what they need to do: avoid defeat and they will reach the last 16 of the Champions League for just the second time.
Unfortunately, their task is not simple. Jens Keller's team have rather underachieved in the CL and Bundesliga this season (particularly in the two matches against Chelsea), but in Julian Draxler (see above) they have the most exciting German talent outside the country's Big Two. They have also managed to lose to both Hoffenheim and Borussia Monchengladbach in the last week, but will still be favourites to progress.
After taking six more points from Chelsea than their opponents, it would be sloppy if Basel then had to settle for the Europa League. Mohamed Salah may be the man to stop such an eventuality.
Atletico Madrid v Porto - Group G, Sky Sports 4 - Red Button (Wednesday, 19:45)
Not much not to dislike about either side in the Falcao derby, but a match that means a great deal more for the away side thanks to Atleti's mightily impressive 13 points from five games. No team holds a greater lead at the top of their group than Diego Simeone's side, who are rather enjoying their first Champions League campaign for four years.
Porto, meanwhile, look on the verge of elimination, and coach Paulo Fonseca is under increasing pressure after the club suffered their first defeat in 53 league games. Porto's supporters clearly have reasonably higher standards, as they crowded around the team bus and threw flares at the vehicle.
If that's the reaction to sitting third in the table and two points off the lead, then the squad have as much incentive as they need to not miss out on a last-16 place to a Zenit St Petersburg side that have won just one of their five games in the group stage. Their welcome home at the airport could be frosty, at best.
Milan v Ajax - Group H, Sky Sports 4 - Red Button (Wednesday, 19:45)
After a phenomenal comeback in Group H, Ajax have the chance for complete redemption in a rerun of the 1995 final - think Overmars, Davids, Desailly, Baresi, Rijkaard et al. Frank de Boer was also playing that night, and knows a repeat of the 1-0 scoreline would see his side qualify for the last 16 at Milan's expense.
Having gained one point from their opening three matches, that would be one hell of an effort, but having beaten Barcelona last time out, there is no reason for a lack of belief. Milan have not won in four matches at the San Siro, have just one victory in seven Serie A matches and are currently sat limply in ninth directly behind Genoa, Torino and Verona.
For their part, Ajax have now won six matches consecutively in all competitions, conceding just once during that period, and in Viktor Fischer and Davy Klaassen the Dutch champions they have two of the Eredivisie's brightest young talents.
Napoli v Arsenal - Group F, Sky Sports 2 HD (Wednesday, 18:00)
Given Arsenal's frankly outrageous current away form (it's now 15 wins and a draw from their last 17 on the road), one would suspect that qualification is all but sewn up, but a defeat by a greater scoreline than the 2-0 Arsenal win at the Emirates in October would still see the Gunners eliminated if Dortmund beat Marseille. A draw would be enough to confirm Arsenal's place atop the group - a fantastic achievement given the strength of opposition.
For Napoli and Rafa Benitez, it is out of their hands. They are unlikely to beat Arsenal by three clear goals, and must instead await news from the south of France as to any German slip-up, needing to better Jurgen Klopp's side's result to progress. Current form won't provide much confidence either, as a run of five wins in a row has been followed by one win in five, and eight goals have been shipped in three games.
A strikeforce of Gonzalo Higuain and Goran Pandev (five goals in their last two starts together) will always provide cause for hope for the Italians, but it very much looks as if Napoli will be the losers in proving that three simply doesn't squish into two in the Champions League's Group of Death Hard Games.