Barcelona will likely need a result against Bayern Munich midweek in the Champions League to have any chance of advancing past the group.
It's a do-or-die situation for new man Xavi and all at Camp Nou. A group stage exit would mark their earliest departure for 21 years.
You have to go back to the 2000/2001 season for Barcelona's last failing at the first post. That team has now become a who's who of managers.
Pep Guardiola was club captain back then and has gone on to become one of the world's best coaches. Spanish manager Luis Enrique was also in that squad.
Then there's the less impressive Frank de Boer and Philip Cocu as well as the aforementioned Xavi. There must have been something in the water.
The head coach at the time was Lorenzo Serra Ferrer. A man who was most known for his days at Real Betis in La Liga. He didn't last the full season.
Not even Ferrer could have predicted that Leeds United would be one of the main reasons he got his walking papers months later.
Heading into the 2000/2001 Champions League season, Barcelona were drawn in Group H with AC Milan, Leeds United and Besiktas.
Their European form wasn't questionable. They made it to the semi-finals a year previous and fell to rivals Valencia despite winning one leg.
Domestically they had just finished second to a stellar Deportivo La Coruña team and had made some acquisitions in the summer to bolster their squad depth.
Barcelona spent a massive €63 million on two key signings in particular; Emmanuel Petit and Marc Overmars - who both joined from Arsenal.
October 24th, 2000, was the date when they'd learn their Champions League faith. Having thrashed Leeds 4-0 in their first meeting, it was all on the table at Elland Road.
Rivaldo was Barcelona's main man but it was Patrick Kluivert who had his way with the Leeds United defense a month earlier scoring twice.
David O'Leary had gone with a five-back that day with Gary Kelly and Ian Harte on the flanks. He decided to change things up in their next meeting.
In came a young Jonathan Woodgate in the heart of the defense. Leeds were without a number of their regulars for the decisive fixture.
Another big change was upfront. Alan Smith was the preferred option behind the striker in both games. Mark Viduka came in for Michael Bridges in the second fixture.
Mathematically - Leeds United and AC Milan were tied top with seven points. Barcelona were on four and desperately needed all three points.
They'd succumbed to a surprising 3-0 loss to Besiktas before - who proved to be a bit of a fortress at home having not lost in Turkey in the competition.
The game got off to a flyer for Leeds as Lee Bowyer managed to score inside the first five minutes. His free-kick caught Dutruel off his guard in the Barcelona net.
The Leeds midfield had to contend with Cocu, Enrique, Xavi and Simão but Barcelona were matched for creativity despite a dogged looking line.
A youthful Paul Robinson came to the rescue to keep Rivaldo and co out in the first half. Alan Smith and Mark Viduka showed brilliance in their trickery up top.
The second-half wasn't as smooth for Leeds however. Barcelona began to find their form and tested Robinson on multiple occasions.
Alfonso came close with a header, Rivaldo had a string of free-kicks that hit the target and he even had a goal ruled out for offside.
The tackles were flying and there was a magical atmosphere at Elland Road. Barcelona were knocking at the door but time and time again they were denied.
Leeds didn't give anything up for 90 minutes. They allowed some shots on goal but battled until the very end and looked like a team that belonged with the best.
In the dying minutes - Rivaldo eventually found his way past Paul Robinson. Elland Road was electric at this point - and boos rang out around the stadium.
Ian Harte nicely kicked for touch after the restart in the 94th minute and that was that. Leeds United had taken a lifeline away from Barcelona.
That was the year Leeds went on a run to the semi-finals of the competition. They drew with AC Milan two weeks later and came second in the group.
Barcelona were dumped out despite beating Besiktas. 21 years later - they've never seen a night like that since.