The treble is so rare in English football that when Sir Alex Ferguson addressed his players at Camp Nou ahead of the 1999 Champions League final, he likened it to flying to the moon.
Manchester United had already lifted the Premier League trophy and the FA Cup during the previous 10 days, standing on the verge of becoming the first English team to win all three competitions in the same season. But despite his rousing speech before kickoff, Ferguson realised very quickly that even for an outstanding team, the final game of a gruelling season spent fighting on three fronts was 90 minutes too far. Bayern Munich were better, except during three minutes of stoppage time when Teddy Sheringham and Ole Gunnar Solskjaer scored the goals that wrote United into the history books.
It's been nearly a quarter of a century, but Pep Guardiola and Manchester City are two games away from joining them. The Premier League is already theirs, while all that stands between them and the treble is an FA Cup final against United on June 3 and a Champions League final against Inter Milan a week later on June 10.
Like Ferguson 24 years ago, it's up to Guardiola to plot his way through the remaining three weeks of the season and make sure City don't miss the chance to reach the moon.
City's run-in -- so far -- has been far more serene than the one United experienced in 1999. Guardiola's team rattled off 12 straight league wins to overhaul Arsenal at the top of the table, won their FA Cup semifinal against Sheffield United 3-0 and thrashed Real Madrid 4-0 in their Champions League semifinal second leg.
United, in contrast, drew four of their last eight league games and had to beat Tottenham Hotspur at Old Trafford on the final day of the season to win the Premier League. Their FA Cup semifinal against Arsenal went to a replay, in which Roy Keane was sent off and Peter Schmeichel saved a Dennis Bergkamp penalty, and in the Champions League semifinal second leg against Juventus, United were 2-0 down in 10 minutes. Against Bayern in the final, they were behind for 85 minutes before Sheringham's equaliser.
Since City last lost a game, to Tottenham on Feb. 5, they've been behind for a total of 41 minutes -- 10 minutes against Liverpool in April, and a little over 30 minutes against Real Madrid in the Bernabeu in May. If United's treble is remembered for being wonderfully chaotic, City's charge has, for the most part, been calm and controlled.
The nature of United's run-in meant that from Old Trafford, to Wembley and on to Barcelona, the players were riding a wave of momentum. Training was limited as much as possible to preserve energy, and the most running they did was when Schmeichel chased Dwight Yorke in anger because the striker had scored a Panenka penalty while the squad practiced spot kicks before the Champions League final. (The goalkeeper only calmed down when Yorke swore that he was taking the exercise seriously and he planned to do the same against Bayern.)
Guardiola's dilemma between now and the FA Cup final is how to maintain the rhythm of his key players, like Erling Haaland and Kevin De Bruyne, without putting too many more minutes in their legs or risking injury. City's remaining league games against Brighton & Hove Albion and Brentford -- with nothing at stake -- present a problem for Guardiola because he believes two poor performances could impact the game against United.
"I don't know if they have that feeling to play against Brighton and Brentford at this point, in those terms, because the target for the Premier League is done, but we cannot drop much, otherwise it makes it more difficult," he told a news conference on Tuesday. "The demanding FA Cup final against Man United will be really, really difficult, and I've started to watch a little bit some minutes of Inter Milan and I'm really impressed, really impressed at what they do."
It's a twist of fate that City are looking to match a feat first achieved by United, their city neighbours, and it's United, along with Inter, who stand in their way.
When Liverpool were aiming to become the first English team to do the treble in 1977, they were beaten by United in the FA Cup final in between lifting the First Division title and the European Cup. Liverpool were English football's dominant force for much of the 1970s and 1980s, winning 11 league titles and four European Cups in two decades between 1970 and 1990, but 1977 was as close as they got to the treble. And despite all of United's dominance under Ferguson -- 13 league titles, five FA Cups and four Champions League finals -- it all came together just once in 1999.
Guardiola and City are next to stand on the brink of history. As United can tell them, the chance doesn't come around very often.