To be crowned champions of Europe is a phenomenal accomplishment in itself, but to successfully defend your continental crown requires a team of legendary skill and resilience.
Nine teams have achieved back-to-back UEFA Champions League/European Cup wins since the competition began in 1955, and only one club have retained their UEFA Champions League crown since the tournament was rebranded in 1992/93.
Paris Saint-Germain became the latest, defeating Arsenal on penalties during a cagey final in Budapest.
We've delved into the history books to reflect on the teams that have gone back-to-back in Europe's elite club competition.
Real Madrid
You won't be shocked to see the domineering force in European football have gone back-to-back in the European Cup/UEFA Champions League.
In fact, Real Madrid didn't just successfully defend their crown; they won the first five editions of the European Cup.
Again, Los Blancos don't do things by halves, and between 2016 and 2018 they won the UEFA Champions League three years running in Zinedine Zidane. At present, they remain the only team to successfully defend their title in the UEFA Champions League era.
Benfica
Benfica were the first team not named Real Madrid to lift the European Cup as they ended Los Blancos' dominance by defeating Barcelona 3-2 in the 1961 final.
Featuring legendary figures in the shape of Eusebio, Jose Aguas and Mario Coluna, Benfica retained their crown in 1962 with a 5-3 victory over Real Madrid, despite a first half hat-trick from Ferenc Puskas.
Benfica were 90 minutes away from a three-peat in 1963 but were conquered 2-1 by Milan in the final at Wembley.
Inter Milan
Milan's route to European Cup glory in 1963 sparked a brief period of Italian dominance on the continental stage, but it was their arch-rivals Inter who stormed to back-to-back successes in 1964 and 1965.
Inter conquered two former champions in both finals as they toppled Real Madrid 3-1 in Vienna before the stars aligned for them to achieve European Cup glory at the San Siro with a 1-0 win against Benfica.
The Nerazzurri added a further European crown to their collection in 2010 under the genius of Jose Mourinho.
Ajax
The start of the 1970s belonged to the Netherlands and after Feyenoord were triumphant in 1970, the next three years belonged to Ajax.
Transformed from relegation candidates to the best side in all of Europe, Runis Michels' 'Total Football' inspired Ajax to glory in 1971 as they beat Panathinaikos 2-0 in the final at Wembley.
Michels subsequently departed for Barcelona, and although he declared he'd taken Ajax as far as he could, his successor Stefan Kovacs had other ideas.
Dutch football's favourite son, Johan Cruyff, scored twice as Ajax overcame Inter in the 1972 final in Rotterdam, and the Eredivisie giants joined Real Madrid in accomplishing the three-peat by edging Juventus 1-0 in the 1973 showpiece in Belgrade.
Bayern Munich
You wait several years for a three-peat and then two come along at once.
In the only European Cup/UEFA Champions League final that's required a replay, Hans-Georg Schwarzenbeck's last-gasp strike ensured Bayern forced Atletico Madrid to a second match in the 1974 final and they were ruthless 4-0 victors two days later.
With a team centred around the great Franz Beckenbauer and the prolific Gerd Muller, Bayern asserted their authority on the European stage as they beat Leeds United 2-0 in the 1975 final before completing the hat-trick in the 1976 showpiece with a 1-0 win over Saint-Etienne.
Liverpool
The 1970s: a decade where successfully defending your European Cup title was in fashion.
Following Ajax and Bayern Munich's period of supremacy, Liverpool became the first English club to be crowned champions of Europe in 1977 as they defeated Borussia Monchengladbach in Rome and they repeated the feat in 1978 by overcoming Club Brugge at Wembley.
The Reds were agonisingly close to repeating back-to-back European Cup honours as they toppled Roma in 1984 before losing to Juventus 1-0 in the 1985 final.
Nottingham Forest
English teams dominated the European Cup for six years following Liverpool's maiden triumph in 1977 and Nottingham Forest followed in their footsteps by successfully defending their continental crown in 1980.
Under the stewardship of the legendary Brian Clough, Forest's 'Miracle Men' conquered Malmo 1-0 in the 1979 final in Munich and were victorious again 12 months later as they beat Hamburger SV by the same scorline in Madrid.
It was a remarkable achievement considering Forest were 13th in the old Division Two when Clough first waltzed through the door in January 1975.
Milan
One of Europe's most successful clubs, Milan had already won the European Cup on two occasions before they went back-to-back in the late 1980s.
The early 1980s were a bleak period by Milan's towering standards, but they returned to the European summit under the ownership of Silvia Berlusconi. The president appointed Arrigo Sacchi, signed the Dutch trio of Marco van Basten, Ruud Gullit and Frank Rijkaard and the rest is history.
With Franco Baresi marshalling the backline, Milan were triumphant in the 1989 final with an emphatic 4-0 win over Steaua Bucharest and they defended their crown a year later as Rijkaard's second half goal saw them topple Benfica in 1990.
Paris Saint-Germain
Luis Enrique has assembled one of the great modern sides during his tenure in the French capital.
Paris Saint-Germain had waited their whole existence to win the Champions League until Enrique came along and delivered two in consecutive years.
Flair attacking talents such as Ousmane Dembele, Khvicha Kvaratskhelia and Desire Doue make Le Parisens lethal going forward and they are underpinned by a classy midfield trio containing Vitinha, Joao Neves and Fabian Ruiz.
First they thrashed Inter 5-0 at the Allianz Stadium before seeing off Arsenal on penalties in Budapest 12 months later. Only two sides in the history of the game have completed the three-peat, but you couldn't rule PSG out heading into next year.
