Eight other places are up for grabs when the groups end on Tuesday and Wednesday.
AFP Sports looks at what's at stake on Tuesday:
Manchester United (ENG) vsShakhtar Donetsk (UKR)
Smarting from their fifth Premier League defeat of the season, already qualified Manchester United host Shakhtar seeking some much needed European solace. United's second successive home defeat, a 1-0 reverse to Newcastle on Saturday, has taken much of the gloss off their superb 5-0 rout of Bayer Leverkusen a fortnight ago, a demolition which sealed their passage to the knockout stages. David Moyes will want a quick and sharp response from his team which he said had lacked sparkle against Newcastle, a loss which left the Premier League titleholders 13 points off leaders Arsenal. A draw is essential to take Group A honours and give United a much needed boost ahead of the crammed Christmas domestic programme. Shakhtar, in buoyant form at home -- they lead their league by five points -- must match Bayer Leverkusen's result to qualify. Victory for the Ukrainians would deprive Moyes' men of top spot. United are boosted by the return of Wayne Rooney, suspended for Saturday's game.
Real Sociedad (ESP) vs Bayer Leverkusen (GER)
Leverkusen will qualify for the last 16 at the expense of Shakhtar as long as they see off winless Real and the Ukrainians lose at Old Trafford. A draw will be enough for Leverkusen if Shakhtar lose thanks to their superior head-to-head. Leverkusen have painful memories of their last trip to Spain, a 7-1 drubbing at Barcelona in the 2011/2012 round of 16 -- their heaviest ever European defeat. Bayer go into the tie on the back of a hard fought 1-0 win over Borussia Dortmund to leave them four points shy of Bundesliga leaders Bayern Munich.
Galatasaray (TUR) vs Juventus (ITA)
A draw would be enough to see Juventus through to the knock-out stages, given their better head-to-head record against Copenhagen than Galatasaray's, but even a draw is a tall order in the Istanbul cauldron the Turks call home. It is made even more so by the fact that the Turin club were dealt a severe blow with the news that influential playmaker Andrea Pirlo will miss what is their most important test of the season so far with knee ligament damage, which is expected to sideline him until the New Year -- by which time Juve's Champions League campaign could be a fading memory.
FC Copenhagen (DEN) vs Real Madrid (ESP)
Copenhagen have only pride left to play for as even an unlikely victory over Real would leave them in third place in the group and out of the competition. Real, on the other hand, have cruised through their campaign so far, scoring at will, most recently with the 4-1 drubbing of Galatasaray which, ironically, rekindled rivals Juventus' hopes of progressing. Despite being already qualified, coach Carlo Ancelotti is expected to line out with stars Gareth Bale and Cristiano Ronaldo.
Benfica (POR) vs Paris Saint Germain (FRA)
The hosts have more to play for than the visitors, who are already assured of being group winners. Benfica, though, must better the result of Greek side Olympiakos if they are to reach the last-16. Benfica do have a bit of a hold over the French visitors in that they have beaten them in Lisbon on the last two occasions they have played there. Much could depend on what sort of side PSG coach Laurent Blanc selects, whether he opts to rest several first team regulars or throws them all in as they seek to better their overall points haul of 15 -- they presently have 13 -- from last year's group stage. Lisbon is hosting the Champions League final but it is unlikely that Benfica will emulate Bayern Munich in appearing in a final on home turf given their qualification is out of their hands.
Olympiakos (GRE) vs Anderlecht (BEL)
The Greek side should logically seal their place in the knockout stages at home to a Belgian outfit which has garnered just one point from their five games -- albeit a draw with PSG -- and whom the hosts trounced 3-0 in Belgium with Kostas Mitroglou scoring a hat-trick. Coached by former Spanish great Michel, who was part of the Real Madrid team that overturned a 3-0 deficit in a UEFA Cup second round clash in the 1984/85 campaign to win 6-1 in the return leg, Olympiakos are bidding to reach the Last 16 for the first time since 2009/10. Anderlecht will finish bottom of their group for the seventh successive season they have competed in the competition.
Bayern Munich (GER) vs Manchester City (ENG)
Defending champions Bayern, buoyed by a 7-0 demolition of Werder Bremen on Saturday which extended their unbeaten Bundesliga run to 40 matches, are already through to the last-16. They will win the group with a draw or with a defeat that is no bigger than their 3-1 away victory in Manchester in the teams' first game. Bayern have won 14 of their last 16 home Champions League fixtures, most recently a 5-0 success against Victoria Pilsen on matchday three while their 3-1 win at CSKA Moscow a fortnight ago broke Barcelona's record for consecutive wins with their tenth straight victory. City coach Manuel Pellegrini is hoping to have Spanish playmaker David Silva back from injury. The Spanish attacking midfielder has missed City's last five matches due to a calf injury. Germany captain Philipp Lahm could return for Bayern having missed the last few weeks with a hamstring injury, but Bayern are definitely without winger Arjen Robben who has a thigh problem.
Viktoria Pilsen (CZE) vs CSKA Moscow (RUS)
Neither side can make the last-16, leaving a battle to finish third and claim a spot in the Europa League knockout rounds. The Russians will come third with a draw or with a defeat that is not greater than their 3-2 home success against Viktoria. Pilsen have lost both home games so far in Group D without scoring a goal but had won ten of their preceding 11 home fixtures in UEFA competition, including three in a row in this season's qualifying rounds. Before losing at Bayern (3-0) and City (5-2), CSKA were on a run of just two losses in 11 away outings in UEFA competition.