The humble club based in Miranda de Ebro in northern Spain pulled off a huge upset when they scored in added-time in the quarter-final second leg to snatch a 2-1 comeback win that gave them a berth in the last four.
The 4-4 aggregate result, which put Mirandes through on away goals, prompted a pitch invasion by ecstatic fans at the club's 6,000-capacity stadium and set up a semi-final against Athletic Bilbao or Real Mallorca.
Mirandes, whose annual budget is around 1.2 million euros, had disposed of La Liga clubs Villarreal and Racing Santander in earlier rounds and it was only the second time a team from the third level of Spanish football has reached the last four of the King's Cup.
"Miranda de Ebro has found a place in the hearts of all Spaniards," columnist Tomas Roncero wrote in sports daily As on Wednesday.
Tuesday's "miracle" had made up for the disappointment of Mirandes narrowly missing out on promotion to the second division at the end of last season, Roncero added.
"Superheroes!" read the headline in As' rival Marca. "Mirandes have delighted Spain with their football, their passion, their effort, their confidence, their humility and their joy," the paper added.
STARK CONTRAST
The scenes of jubilation at the Anduva stadium marked a stark contrast with the bickering that has further soured relations between Real and Barca since the Catalans won last week's quarter-final first leg at the Bernabeu 2-1.
The alleged stamp by Real defender Pepe on the hand of Barca's World Player of the Year Lionel Messi was the latest in a series of ugly incidents in games between the arch rivals, who play their second leg at the Nou Camp later on Wednesday.
Portuguese international Pepe said he did not mean to tread on Messi's hand and the Spanish football federation (RFEF) took no action, meaning he is free to play if fit.
Barca coach Pep Guardiola sought to calm the waters on Tuesday, telling a news conference Pepe should be left in peace.
"If they pick him, let him play and that's that," he added. "Let's forget about the past and make the game as entertaining as possible."
