Chelsea became the latest team to qualify for the UEFA Champions League knockout stages though it was not in the fashion manager Jose Mourinho would have wanted as the 2012 champions lost 1-0 to Basel on Tuesday.
However, with Schalke only drawing 0-0 away at bottom side Steaua Bucharest the permutations work out in Chelsea's favour as they lead Basel by a point with Schalke another point back and the latter two play each other in the final group game.
They were the only side to progress from Tuesday's action with the result of the night coming in Amsterdam where a young Ajax side rolled back the years for the former European greats to hand Barcelona coach Gerardo Martino his first defeat in 21 games with a stunning 2-1 win.
This despite playing most of the second-half with just ten men after Joel Veltman was sent off for a foul on Neymar and Xavi converted the penalty to get the Spanish champions back into the match.
However, the Dutch side held on with their two goals in the first-half from Thulani Serero and Danny Hoesen proving sufficient to record a famous victory.
Milan's 3-0 win in Glasgow over Celtic eliminated the Scottish champions from the knockout stage picture -- they won't even get a chance at the Europa League either -- and sets up what is sure to be a nervy encounter with Ajax in a fortnight for the second spot in the Last 16.
Barcelona need to beat Celtic to ensure they finish top of the group.
Arsenal close to advancing
Chelsea's English rivals Arsenal did what they needed to do to give themselves a chance of qualifying by beating pointless French outfit Marseille 2-0 with Jack Wilshere grabbing a double.
The England star's first came after only 27 seconds, the fastest in this season's competition and also the fastest ever by an Englishman - Wayne Rooney the previous holder with one in 65 seconds.
However, they will have to wait till the final round of matches after last season's finalists Borussia Dortmund produced an excellent 3-1 home win over Napoli to keep alive their hopes of reaching the Last 16 - defeat would have seen them go out.
Although Napoli got it back to 2-1 midway through the second-half Gabon striker Pierre-Emerick Aubameyang scored a deserved third and with them due to travel to Marseille for the final match they will be fancying their chances of making it through.
At the Estadio do Dragao, Roman Kienast stunned the Portuguese crowd by scoring Austria Vienna’s first Champions League goal this season. It took until the second half for Porto to pull level, as Jackson Martinez rose highest from a set-piece to nod past Heinz Lindner.
The visitors are out of Europe this season and Paulo Fonseca’s side face an uphill task to reach the Champions League knockout stages, needed a win at the Vicente Calderon on the final matchday.
An error from Atletico Madrid goalkeeper Thibaut Courtois allowed Zenit St Petersburg to snatch a vital point against the high-flying Spaniards as they drew 1-1 in Russia earlier Tuesday.
An under-strength Atletico, already assured of a pass to the knockout stages as Group G leaders, had taken the lead eight minutes into the second-half when Adrian Lopez broke clear of the Zenit defence and finished confidently low past Juri Lodigin.
However, the Russians were saved 17 minutes from time when Courtois allowed team-mate Toby Alderweireld's looping header to drop into his own net to end Atletico's 100 per cent record in the Champions League so far this season.