Winning the league, domestic cup, and Champions League in one season.
Definition: Winning the league, domestic cup, and Champions League in one season.
The Treble is the holy grail of European football — winning all three top trophies (domestic league, domestic cup, Champions League) in a single season. Only 8 clubs in history have done it. Famous Trebles: Manchester United 1999, Barcelona 2009, Inter Milan 2010, Bayern Munich 2013 and 2020, Manchester City 2023.