If anything in football proves that hope springs eternal, it is Manchester City's conviction that victory can be achieved at Barcelona four days after City's home defeat to Wigan.
Manuel Pellegrini's men travel to Spain 2-0 down from the first leg as they bid to reach the quarter-finals of the Champions League for the first time, and with another FA Cup humiliation at the hands of their second-tier neighbours still smarting – a "hangover", as midfielder Samir Nasri put it.
Of course it's difficult. But I don't have any doubt that we are going to Barcelona thinking that we can do it, that we can beat them in Camp Nou and we will try to have our revenge there.
But if there is something to be gained from their cup exit it is the reminder that some of the lowliest underdogs can deliver a deadly bite, as City themselves have done against top opposition in Europe this season.
Their last away game in the Champions League saw them come from two goals down to defeat holders Bayern Munich 3-2, and City's super-rich Emirati owners have built a team that is capable of beating any side in the world.
Victory is a tall order, despite Barcelona's surprise defeat to Real Valladolid at the weekend reinforcing the idea that the Catalans – European champions three times in the last eight years – are not the force they were.
Only Ajax Amsterdam in 1996 and AC Milan in 2011 have gone through after a home defeat in the first leg.
But in Sergio Aguero, City have a striker on 26 goals for the season and who is used to finding the net against Wednesday's rivals, having scored five times in 10 La Liga games against Barca for Atletico Madrid.
"As always in important games the individual performance of players is key," Pellegrini, speaking to the club's website, said of the Argentine who was injured for the first leg.
"Of course it's difficult. But I don't have any doubt that we are going to Barcelona thinking that we can do it, that we can beat them in Camp Nou and we will try to have our revenge there."
Nasri, who scored in Sunday's 2-1 cup defeat, said there were positives to be taken from their siege of the Wigan goal in the final stages.
"The big disappointment is that it is twice now that Wigan have beaten us in the FA Cup," the Frenchman said. "It is really difficult to accept. It is like, they gave us the FA Cup on a plate and we refused to take it.
|Lionel Messi has scored seven goals in four Champions League matches including the opener in Manchester [EPA]
"I think we have nothing to lose. Just attack them from the start and try to score an early goal."
Barcelona will make their seventh straight appearance in the quarter-finals if they hold on to their lead, with the club's management more concerned about damage to their reputation surrounding the summer transfer of Neymar than Real Madrid's three-point lead at the top of La Liga.
Club president Josep Maria Bartomeu said on Monday that Barca had done nothing wrong in the deal with Santos, which was initially disclosed as $74m but was revealed at $118m after they were accused of tax fraud.
The Catalans later paid an extra $18.7m to cover possible differences in 'interpretation'.
"Barcelona acted in the proper way but if somebody thinks that there is damage to the name of Barcelona then there is damage to be repaired," Bartomeu told the BBC.
On the pitch, Chilean forward Alexis Sanchez said his team were far from finished, and were champing at the bit to finish the job started by goals from Lionel Messi and Dani Alves in Manchester last month.
"I am hungry to win and so are all my team mates," he said of the City game. "We want to win everything, La Liga, the Champions League and the Copa del Rey. I don't know anyone in the squad who doesn't want that."
Wednesday's other last-16 second-leg tie sees Paris Saint-Germain defend a 4-0 lead against out-of-form Germans Bayer Leverkusen at the Parc des Princes.