In the aftermath of Barcelona's 2-0 defeat at Milan, Xavi Hernández was putting on a brave face. "The one thing that is missing for this generation of players is an historic remontada," he said. A remontada is a comeback; the trouble is, it's not really Barcelona's thing. It is Real Madrid who have made a very public virtue out of the remontada, starting when they beat Derby County 5-1 back in 1976, having lost 4-1 in the first leg, and becoming a regular occurrence during the mid-1980s.

And yet the task before Barcelona on Tuesday night has been achieved before. They have never overturned a 2-0 first-leg lead, as they must do now, but they have gone one better and come back from 3-0 down three times: in the 1977-78 Uefa Cup against Ipswich, in the 1978-79 Cup-Winners' Cup against Anderlecht and most famously and dramatically of all in the European Cup in 1985-86.

Having won the league title for the first time in 11 years under Terry Venables the previous season, this was only the fourth time that Barcelona had even competed in the European Cup. They knocked out Sparta Prague on away goals, did the same against Porto and then beat Juventus 2-1 on aggregate. In the semi-final, they faced the Swedish side Gothenburg.

When the draw was made, Barcelona's players were dancing round the dressing room celebrating, but on a frozen pitch they lost the first leg in Sweden 3-0 and they were fortunate it was only that many. So dominant had the Swedes been that as the game went on Venables chose not to chase the score but to protect it, giving his team a tiny glimmer of hope in the return match. The second leg was at the Camp Nou on 16 April, 1986. "And that night," says the striker Pichi Alonso, "the Virgin appeared."

In fact, it was Pichi Alonso himself who appeared. Presenting highlights of the game on the TV programme Saint and Greavsie a few days later, Ian St John announced that Pichi Alonso was Barcelona's third-choice striker. Jimmy Greaves interrupted to correct him: "He says he's their sixth [choice], Terry." He had played just five minutes in the European Cup and even as Barcelona trailed by three in Gothenburg, even with Steve Archibald injured, he had not been brought on. The second leg could hardly have been more different.

Pichi Alonso will forever be remembered for that night. As he himself puts it, with a touch of embarrassment: "Víctor Muñoz played 32 times as many games as me but no one remembers him – they remember me." The Catalan satirical TV show Crakóvia has the character playing him walk on set to perform a version of Abba's Waterloo, with the lyrics changed to Gothenburg, describing what happened as a "paranormal experience". That night he scored a hat-trick, almost a quarter of all the goals he scored in his four-year Barcelona career.

Marcos Alonso had insisted in the buildup to the game that Barcelona would get the three goals they needed before half-time but it took a bit longer. Pichi Alonso bundled through for the first nine minutes in, controlled a long ball and finished neatly for the second just after the hour, and reached Lobo Carrasco's cross for the third on 69, his header going so far into the ground that it bounced back up again and looped fortunately over the goalkeeper Wernersson; 3-0 on the night, 3-3 on aggregate. Two minutes later, Venables took off an exhausted Pichi Alonso , and the game went to penalties.

Francisco Javier González Urruticoechea, "Urruti" – the man who had taught Archibald to swear with the aid of a pen, a piece of paper and pictures of body parts – had saved the penalty in Valladolid that clinched the league title. Now he was set to be the hero again, taking the shootout into sudden death by saving when Gothenburg were on the verge of reaching the final, and then scoring the next penalty himself; 3-3 on aggregate, 4-4 on penalties. It was left to Víctor Muñoz to take the decisive spot-kick to send Barcelona into their second ever European Cup final, two decades later.

As Muñoz celebrated, a delirious ballboy in a Barça tracksuit sprinted over, grabbed him by the arm and pleaded for his shirt. His name was Pep Guardiola.