For the Spurs, the prospect of the first trophy since 2008 is also a chance to save something from a desperate Premier League campaign, which, like Manchester United, redefines what the family fails at the so-called Big Six club.

Their season also saw angry fan protests, a protest in the way club owner Enic lacked investment and chairman Daniel Levy.

"Qualification for the Champions League will be the ideal category for the Spurs, not essential," Maguire said.

"They are the best businesses running in the Premier League. They have the most profitable history. They have the ability to make money from non-football events to a much greater extent than any other club, so they always use it as a support mechanism."

At Manchester United, the Champions League's second straight season means the club will have to pay a £10 million fine to kit provider Adidas under the terms of its deal.

A former senior United person said on condition of anonymity that if they leave Europe for the second time in 35 years, the club is proud of their sponsorship revenue, and their brand value is now at a critical moment.

They told BBC Sport that “it’s not European teams that create more existing problems around the entire model”, pointing to Tezos sponsorship for the club training suite this summer.

"It's not healthy, and people are starting to question whether you're still a 'big club'. But win, it keeps the wheels spinning. The cash will be 'hit', allowing them to keep trading. If not, they will have to consider selling local talents like Alejandro Garnacho and Kobbie Mainsoo to provide them with fun."

Some Manchester United fans heading to Bilbao hope the match will bring back memories of the 1991 Cup Cup-winning Cup - which helped inspire the subsequent glory days of Sir Alex Ferguson and show that the club can perform again at the European level.

Others will use 2017 as a source of inspiration when Mourinho's side won the Europa League final to save the Champions League qualification and finished sixth in the Premier League. But, given that Manchester United's league performance is getting worse, it feels even more important.

Losing to the Spurs, many people will feel that Ineos' already ambitious Mission 21 plans to turn United into Premier League champions in 2028, which seems impossible. However, senior joint insiders have suggested that this is a “win or bankruptcy”, insisting that the club’s ongoing cost-cutting plan is designed to give flexibility in the summer transfer window and have already made predictions in the absence of Europe.

While they accept that winning the Europa League will provide a significant boost, they say the key is repairing the club's structure.

Amorim and his peers, Spurs owner Ange Postecoglou, both made suggestions about some kind of magic bullet for the Europa League. Indeed, as the Spurs also played in the worst Premier League season of all time, the victory may not be enough to get Postecoglou to work on his job, and Amorim appears to be in his team, even if his team loses.

However, there is no denying that Wednesday is still full of dangers, making it one of the most eager games of the season.

While neutrals may enjoy danger, Manchester United and Spurs fans will crave hopes of much hope at the end of a season. In Bilbao, a city known for its rebirth, has the opportunity to start a revival.

However, the loss, recovery road feels longer.