Real Madrid and AC Milan have 16 Champions League titles between them but both have work to do on Wednesday if they are to book their places in the next round of this season's competition.
The teams are neck-and-neck on seven points in Group C and will both go through if Real overcome Swiss champions FC Zurich at the Bernabeu and Milan defeat Marseille at the San Siro.
Neither side can afford any slip-ups, though, as Marseille are just a point back in third place with two games remaining.
“This game against Marseille on Wednesday will be very difficult, against a team that plays a bit like us,” said Milan's Brazilian boss Leonardo.
Fate drew Real and Milan together at a time when both clubs were reeling from disappointing showings last season, when they were each forced to stand aside as their fiercest rivals swept all before them.
Real, nine-time champions, could only look on as Barcelona romped to an unprecedented treble, while seven-time winners Milan saw city neighbours Inter cruise to their fourth straight Serie A title.
A summer of soul searching saw new coaches pitch up at both clubs, while new Real manager Manuel Pellegrini was also granted a multi-million euro squad makeover thanks to the chequebook of returning president Florentino Perez.
{{/usCountry}}A summer of soul searching saw new coaches pitch up at both clubs, while new Real manager Manuel Pellegrini was also granted a multi-million euro squad makeover thanks to the chequebook of returning president Florentino Perez.
{{/usCountry}}Three months into the season both sides appear to be back on track, with Milan having bounced up to third place in Serie A after a stuttering start and Real leading La Liga by one point from Barcelona ahead of next weekend's first 'Clasico' of the season at Camp Nou.
Unlike Milan and Real, four-time champions Bayern Munich are staring down the barrel of early elimination as they lie four points behind Juventus in the battle to nail down the final qualifying place in Group A.
Bayern will be confident of closing the gap at home to winless Israeli outfit Maccabi Haifa, but Juventus visit already-qualified group leaders Bordeaux knowing that victory will take them into the next round.
Juve returned to second place in Serie A by beating Udinese 1-0 on Sunday, but Bayern were held to a 1-1 draw at home to Bundesliga leaders Bayer Leverkusen that left them six points off the top in seventh place.
“We're unhappy, because none of us likes the situation in the league table,” said Bayern chairman Karl-Heinz Rummenigge. “The fans don't like it, the coach doesn't like it, the team doesn't like it, and neither do I, naturally enough. We need a big win to relieve the pressure.”
Last season's runners-up Manchester United welcome Turkish champions Besiktas to Old Trafford, having already guaranteed a place in the next phase with a 3-3 draw at home to CSKA Moscow last time out.
German champions Wolfsburg are three points clear of CSKA for the second qualifying place and travel to Moscow needing just a draw to go through.
Chelsea and Porto have already secured their progress from Group D, but the Premier League leaders can secure top spot in the group if they win when the sides meet at the Estadio do Dragao in north-west Portugal. Atletico Madrid will make sure of a consolation berth in the Europa League if they win against APOEL.