European football is the pinnacle for every side on the continent.
For the biggest teams around, it is a measure of success. Just look at the way PSG have operated in recent years for example.
It doesn't matter how many domestic trophies you win, if you don't come home with the Champions League then you're out the door.
It's a trophy that's eluded even some of the best of managers. Arsene Wenger never won it, while Pep Guardiola hasn't been successful in Europe with Bayern Munich or Manchester City.
Zinedine Zidane, however, is a multiple winner of the competition with Real Madrid. Los Blancos have been the dominant force in UEFA's premier competition over the last few years but Liverpool finally dethroned them in 2018/19.
A year on and the crown was now Bayern's again - their 1-0 win over PSG signalled their sixth Champions League win. The French side will have to wait again to win it for the first time.
However, there is a more illustrious list at play here. Whether it was PSG or Bayern that came out on top this weekend, one of them was to become just the 14th side to win a European treble.
Who else appears on this roll of honour, I hear you ask? Well, read on to find out.
Celtic - 1966/67:
The Hoops are used to winning trophies and just a year after England were crowned World Cup winners, Celtic won the European Cup as it was then known.
They won the league with 58 points and took home the Scottish FA Cup after a 2-0 win over Aberdeen.
Ajax - 1971/72:
A team consisting of the great Johan Cruyff, this was when Dutch football was in one of its finest periods. Ajax won the league on 63 points, beat FC Den Haag 3-2 in the Dutch cup final and then defeated Inter in the European Cup final.
IFK Goteberg - 1981/82:
You have to go another ten years to discover a further European treble winner. This is one of the more stranger names on the list, as they beat Hamburg in the UEFA Cup final over two legs and were also crowned Swedish league and cup champions.
PSV - 1987/88:
Another of Dutch football's great sides, they won the European Cup against Benfica after the game went to penalties. Coincidentally, they also won the Dutch cup after extra time. Talk about nerve-racking.
Manchester United - 1998/99:
Name a better duo, I dare you. Man United and Sir Alex Ferguson were always going to feature on this list. They won the Premier League on 79 points, beat Newcastle in the FA Cup final and then defeated Bayern Munich 2-1 in the Champions League final.
Galatasaray - 1999/01:
It's quite incredible that just a year after United's achievement, it was being replicated again. The Turkish giants won the league on 79 points and then won the domestic cup after extra time. Arsenal were the losers in a thrilling UEFA Cup final.
Porto - 2002/03:
Welcome to the limelight Jose Mourinho. This was when everyone stood up and took notice of the Portuguese. They won the league on 86 points and took home the UEFA Cup after extra-time against Celtic. Porto went onto win the Champions League just a year later.
CSKA Moscow - 2004/05:
There have been a number of European treble winners in the modern era but CSKA are one of the most unlikelier names. They defeated Sporting 3-1 in the UEFA Cup final in 2005.
Barcelona - 2008/09:
It took Barca until 2009 to finally seal a European treble. They won La Liga on an impressive 87 points, swatted aside Athletic Bilbao and then beat United in the Champions League final. This was the start of a dominant era in Barcelona's history.
Inter Milan - 2009/10:
This was some side and again it was Bayern that were defeated in the final. This doesn't bode well for them on Sunday evening, does it? Inter won Serie A on a haul of 82 points and beat Roma in the Coppa Italia.
Porto - 2010/11:
The first team to ever win a European treble twice was the Portuguese giants. They demolished Vitoria Guimaraes 6-2 in the Taca de Portugal final and then beat Braga 1-0 in the Europa League climax.
Bayern Munich - 2012/13:
This team was truly ridiculous. They won the league on 91 points, beat Stuttgart in the DFB Pokal final and then defeated German rivals Borussia Dortmund in the Champions League final.
Barcelona - 2014/15:
No team has won the European treble for five years but this Barca side were top-notch. They finished top of La Liga with 94 points and beat Juventus in the Champions League final.
Bayern Munich - 2019/20:
For the second time in seven years, Bayern managed to secure the treble. The final against PSG was no thriller but it was evidence of an organised and frightening side. Kingsley Coman's goal was enough to crown a miraculous job by Flick. It's hard to picture how the same team were beaten 5-1 by Frankfurt last year.
There we have it, a truly honourable list.
It takes quite something to not only win the league title but also the domestic cup and European trophy. It's an absurd amount of matches to play in one season so hats off to the fitness of some of these players that featured.
Remarkably, we've never seen teams like Real Madrid, AC Milan or Liverpool win a European treble which goes to show just how tough it is to do.
Perhaps that should be next on Jurgen Klopp's list of things to achievements to tick off at Anfield? Watch this space.
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