When little Leganes faced Real Madrid in the Spanish Cup quarter-finals this season, their kit man was sent off and subsequently given an eight-match ban.

The referee’s report said that he had ‘repeatedly shouted and waved his arms’ in protest, and that on being dismissed he went for the fourth official and then for the referee again in the tunnel after the game, with phrases such as ‘you’re all bottlers’ and ‘you’ve got no shame’.

You've got to go some to get an eight-game sanction in Spain and Juan Domínguez had earned his month off. In one way it sums up the Madrid minnows this season.

Leganes have done nothing by half-measure. They have displayed spirit – too much spirit in Domínguez’s case – and they have shown no respect for the rank of their rival or the venue.

They lost that first leg at home 1-0, but won the second leg 2-1 at the Santiago Bernabeu a week later (their first win ever over Madrid) to reach the Copa del Rey semi-final.

It had been their first ever appearance at the quarter-final stage of the cup. In their first ever semi-final first leg they drew 1-1 at home to Sevilla. If they can beat Vincenzo Montella’s team on Wednesday night they will be in their first ever final – extraordinary for a team that were in the third tier of Spanish football just four seasons ago.

Asier Garitano has a lot to answer for. The club’s 48-year-old coach was a striker for Alicante in Spain’s second division in his playing days.

This season he has played down the idea that Leganes could be playing European football before long, calling the idea ridiculous, but reaching the Copa del Rey final would all but make certain of it – rivals Barcelona or Valencia would already be in Europe.

Whether Garitano would still be around to see them play their first match in the Europa League is another question. There are plenty of clubs looking at him and Marca’s editorial asked the question after they beat Madrid: ‘What would this man do with top players?’

There are only 11 miles between the 80,000 capacity Santiago Bernabeu and the 11,500 Butarque stadium on the southern outskirts of the city but the two Madrid clubs are world’s apart.

Leganes’ budget is around €45m. Their transfer record was paid last summer for €3m Greek centre-back Dimitris Siovas, and he repaid it with the goal in the first leg of the semi-final - the big-bearded defender making the most of weak goalkeeping to give his team a fighting chance in tonight’s second game.

They also had 33-year-old goalkeeper Nereo Champagne to thank for  a string of good saves. The former San Lorenzo keeper is perfectly named for a season that will end in celebration regardless of what happens on Wednesday.

This is a club that came up from the third tier in 2014. After just two seasons in the second division they were promoted again, despite the huge gulf in quality between those two levels. Garitano was at the helm through it all.

His methodical sessions are often built around defence. There is a painstakingly detailed going over of every given possibility during a game so his players know exactly who they should press and who they shouldn’t, and when they should hold their shape and when they should go after the opposition.

If they do get knocked out, the target for what remains of the season will be to establish themselves as Madrid’s third club behind Real Madrid and Atletico. In the battle of the capital overspill satellite towns they are one place below Getafe in the table. With a population of 190,000 they have more inhabitants. Getafe’s population is 176,000. Getafe were originally formed in 1923 but they were reformed in 1983.

Leganes have been unchanged since 1928, right down to the green away kit, which at various times in their history has been their home kit, and gave rise to the ‘Cucumber Growers’ nickname.

Passions will be running high in Sevilla's cauldron Sanchez Pizjuan stadium. 'It doesn't matter how good the atmosphere is,' says Garitano. 'It will not give them a 1-0 advantage. We have a chance. What we did at the Bernabeu is forgotten now. It's in the past. Sevilla are used to playing and winning finals; for us it is the first time.'

That didn't stop them in the quarter-finals against Madrid. It will be the story of the season if they make it to the final. Juan Dominguez - who has served the club for 20 years coaching various youth teams as well as laying the kit out for the seniors - should be clear to be back on the bench for that one.