Barcelona are braced for feeling like the away team tonight at the Nou Camp if 25,000 Eintracht Frankfurt fans in the city make it into the stadium to support their team.
The club have sold 5,000 tickets to visiting supporters but they took measures on Wednesday to stop German supporters flooding the stadium by preventing anyone from buying a ticket online who did not do so with a Spanish banking card.
Whether that is enough to stop more tickets getting into the hands of Eintracht Frankfurt supporters remains to be seen.
Catalonia is already on Easter holidays with Thursday traditionally a day when people head off, taking advantage of a four-day weekend.
If Barcelona supporters don’t turn up in numbers tonight and their tickets are taken by visiting fans then Barca fear they will not feel the benefits of home advantage going into tonight’s second leg at 1-1 from the meeting last week.
Some Eintracht Frankfurt supporters were involved in trouble with Sevilla supporters and West Ham fans last month when both the English club were in the city of Seville to play Betis as Eintracht faced Sevilla.
So far the invasion has been friendly and around 200 fans from one of the best supported clubs in Germany even turned out to watch lower league Barcelona-based club Europa take on Huesca B on Wednesday night, joining songs with the local supporters.
Xavi needs the Nou Camp behind him as he tries to take Barcelona into the semi-finals of a competition they have never won.
He might have to do so without Gerard Pique who has not joined up with the rest of the squad for the pre-match get together.
It’s still not clear if the player, who has an abductor muscle problem in his left leg, will take a late test to give himself the chance to play in what is being talked up as Barcelona’s first final of the season.