On the November night when Atlético Madrid were knocked out of the Champions League by Qarabag last season, the club captain Gabi Fernández was asked what he thought about the two-time finalists having to drop down to play in Europe’s second competition instead. “At the moment,” he said, “I’d tell you the Europa League is shit.”

If Gabi was often reminded of the first half of the phrase, right up to the day six months on when they lifted the Uefa Cup trophy in Lyon, the second part was largely forgotten. And yet it was important. “But,” he had said back then, “it has given us a lot, and we will try to win it.”

Above all, it had given them a beginning, meaning. On the morning of Atlético’s visit to Copenhagen in the round of 32, the headline in the country’s best-selling sports newspaper Marca said: “It all started with you.”

By then Atlético were what they were, at least in part, because of the Europa League, and there may be some parallel there for Chelsea or Arsenal, a lesson. Just as there might be in Liverpool losing the Europa League final against Sevilla as a prelude to two consecutive Champions League finals.

“We can’t forget what made us strong. I see old Europa League games and we didn’t even have a shirt sponsor Diego Simeone

It is an escape, an access point. And it is not just that winning it provides access to the Champions League, which it didn’t back then; it is that it prepares you for the Champions League. And, in Atlético’s case, for everything else too.

Without the Europa League there would be no Copa del Rey, no league title, no Champions League finals, nothing. This era, their best in three decades, would be unthinkable. Just ask Diego Simeone.

“Everything’s important to me. The Cup, the league, the Champions League, the Super Cup. We look at how games help us keep growing as we’ve done for six years,” he said before last season’s last 16 tie against Lokomotiv Moscow.

“We can’t forget what made us strong. I see old Europa League games and we didn’t even have a shirt sponsor. We do now. We can’t forget if we want to keep growing.”

Atlético Madrid celebrate after winning the 2018 Europa League final, continuing a golden era for the club. Photograph: Matthias Hangst/Getty Images

That went back even before Simeone’s arrival. The 2010 Europa League win under Quique Sánchez Flores may have been overlooked a little since, but it was a start. Atlético finished ninth that season, seemingly in perpetual crisis, yet Europe gave them something to believe in, something to be.

“In Europe we have shown that we are a great team,” defender Álvaro Domínguez told The Guardian. The fact that it was a realistic target motivated them more, he admitted. Last year, Domínguez looked back on that success in El País, precisely as a way of challenging the idea that Atlético’s ‘relegation’ to the Europa League signified their era was over; instead, he said, it could restart them.

“There was a negative atmosphere, people still remembered the relegation [in 1999], there were bad seasons, failed signings,” he recalled. “There were whistles at the Calderón, things were going badly in the league, but the fans connected with the team in those European games. For the club it was a comfort, it calmed everything down and the fans began to believe in the team. We had to activate [everyone] and we did it with the Europa League.”

On the face of it, the effect did not last long but something had shifted a bit – and wouldagain under Simeone. The 2010 Europa League was Atletico’s first title in 14 years and they had suffered relegation since then, sinking into the second division for two years.

It was their first European trophy since the 1962 Cup Winners’ Cup and their first non-domestic success since the 1975 Intercontinental Cup, in Luis Aragonés’s first season as coach. It would also become Simeone’s firsttrophy at Atlético when they defeated Athletic Bilbao in 2012.

The Argentinian had arrived midway through the season, the team recovering and climbing to fifth, just outside the Champions League places. A trophy reinforced the sense that a new era was beginning, strengthening his position. “This is very, very important for me,” Simeone said. It had started and nothing would be the same again.

Simeone’s first season ended with the Europa League. His second started with the European Super Cup and ended with the Copa del Rey, against Real Madrid, at the Bernabéu. His third ended with the league title, clinched at the Camp Nou.

There was a Champions League final too, of course, and another two years after that. Between those there was a Spanish Super Cup. Last season, Atlético made it to the final of the Europa League again, back to where it all began, a reminder of how far they had come.

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If anyone knew how far that was, it was Fernando Torres. Victory in Lyon saw him depart Atlético Madrid with his first title at the club. It made Simeone the most successful manager in their entire history, ahead of Aragonés.

It also allowed Gabi to leave with a seventh winners medal, unthinkable when he made his first team debut for a struggling club fourteen years earlier. Together, he and Torres lifted the trophy, the perfect end. “I’m going to have to eat that ‘shit’ now,” Gabi said afterwards.