The English Premier League's claims to being the best in Europe will be tested this week with three clubs facing UEFA Champions League matches which will decide whether or not they progress to the knockout stages.
Chelsea host Valencia on Tuesday needing to either beat the Spaniards or draw 0-0 to progress - failure to do so will turn up the heat young Portuguese manager Andre Villas-Boas.
Last season's finalists Manchester United have to avoid defeat at Swiss side Basel on Wednesday, while city rivals Manchester City face the toughest task as they host Group A winners Bayern Munich needing to beat them and hope second-placed Napoli lose at pointless Villarreal.
They will be looking to join holders Barcelona, Real Madrid, 2010 winners Inter Milan and city rivals AC Milan, as well as the first Cypriot club to qualify, APOEL Nicosia, in the last 16.
Chelsea will go into the clash with Valencia at least comforted by their 3-0 away win over Newcastle on Saturday - the first time that they have had successive clean sheets in the Premier League since January.
Villas-Boas believes that the victory over the Magpies has given them the necessary boost to get the result they require against the former Champions League finalists. "We now have a major, major game against Valencia," he said. "We hope to get through it and that will set up the right emotional stimulus to take on the league leaders. The results haven't gone our way recently so to find an inner-belief and strength (to win at Newcastle) was a major key."
Valencia too won on Saturday beating Espanyol 2-1, though, their coach Unai Emery wants to see an improvement on that performance against Chelsea. "I think some of the players minds were on Tuesday's match," sighed Emery.
However, he is determined that his players do not go to London just looking for a score draw. "Our mentality will be to go there to win. We'll have a chance in London to see what we are capable of. We will have to play with intelligence and strength and try to enjoy the moment."
Hard road for Red Devils
United have made heavy weather of what on paper looked a relatively easy group but Sir Alex Ferguson's players will travel to Switzerland well aware that Basel are capable of beating them after coming away from Old Trafford with a deserved 3-3 draw.
Basel are in fine form, taking a huge step towards retaining their domestic title with a 1-0 home won over second-placed Lucerne on Saturday that saw them extend their lead to six points and will be keen to ensure United suffer only their third group stage exit.
United also warmed up for the match with a 1-0 win - their fourth such winning margin in five games - at Aston Villa but Ferguson's joy was tempered by an ankle injury that will see Mexican striker Javier Hernandez miss not only the match but probably the busy Christmas programme.
Ferguson was heartened by the goalscoring performance of youngster Phil Jones in the centre of midfield, a role he is likely to have to fill on Wednesday as Michael Carrick is ruled out through suspension. "He's (Jones) a natural centre-back but he is so versatile he can play in any position. We don't have Michael Carrick for Wednesday because he is suspended and we had to look at options."
Manchester City manager Roberto Mancini is realistic about their chances of reaching the last 16 and believes it will take another two years of action at this level for his side to be genuine title contenders. "If we don't go through in the Champions League our lives will continue. We will play in the Europa League and try to win the Europa League. We made some mistakes in this group and this can happen," he said.
Elsewhere all three French clubs are still theoretically in the mix though Lyon need a miracle to survive - having to beat Dinamo Zagreb by seven goals and for Real Madrid to hammer Ajax.
Lille appear the best placed as a home win over Turkish side Trabzonspor will suffice for the French champions while 1992 European Cup winners Marseille must beat bottom-placed Borussia Dortmund to ensure they progress.
A draw though could also see them go through if group winners Arsenal beat Olympiacos in Greece.