Real Madrid and Liverpool will be among teams fighting for the last places in the knockout stage of the Champions League this week when the final group matches decide who goes through.
Seven clubs will join nine who have already secured passage to the 16-team knockout stage of the competition while eight third-placed teams will carry on in the UEFA Cup after the winter break.
The most enthralling battles are in groups and A and C, where all eight teams still have a chance of qualifying.
Liverpool responded to a poor start in Group A with two emphatic home wins that threw them a lifeline and they can avoid an early exit with a win at Olympique Marseille on Tuesday.
A draw will also be enough for 2005 winners Liverpool if Turkish contenders Besiktas, who suffered the competition's record-breaking 8-0 defeat at Anfield, beat group leaders Porto away.
Real Madrid know a draw will be enough against Lazio at home to progress from Group C, where Greek champions Olympiakos Piraeus also need a home draw against Germany's Werder Bremen.
Both away teams could go through with wins, confining nine-time European champions Real to the UEFA Cup.
FIGHTING CHANCE
Rangers need to avoid defeat in Group E at home to French rivals Olympique Lyon, who responded to their opening two losses with two wins and a draw to give themselves a fighting chance at Ibrox.
Lyon will go to Glasgow in confident mood after good recent form. Rangers' weekend Scottish Premier League match with Gretna was postponed to give them more time to prepare for Wednesday's match.
Old Firm rivals Celtic went through with holders Milan in spite of a 1-0 defeat at the San Siro on the final day in Group D, played last week because of Milan's involvement in the Club World Cup in Japan.
Group F winners Manchester United are away to also-qualified Italian rivals Roma on Wednesday in a match that might tempt both managers to rest several first-choice players.
There will be no lack of passion though as Roma should be eager to avenge last season's 8-3 aggregate drubbing by United in the last 16 followed by a 1-0 defeat at Old Trafford in October.
Chelsea are through from Group B before their home match against Valencia tomorrow and either Rosenborg or Schalke will join them with the Norwegian surprise package needing a draw at their Bundesliga rivals.
Fenerbahce will be favourites to join Inter Milan from Group G.
They are at home on Wednesday to eliminated CSKA Moscow and are a point ahead of 1988 winners PSV Eindhoven, who are bidding to reach their fourth successive berth in the last 16.
Arsenal have qualified from Group H and can leapfrog Sevilla into pole position if they beat Steaua Bucharest at the Emirates and the Spanish side slip up at Slavia Prague on Wednesday.
