The Champions League is the most prestigious club competition in European football. It is contested by the national league champions (and, for some nations, one or more runners-up) of their respective UEFA associations and is played in a group stage before a single-elimination knockout tournament. It is considered to be the top club competition in the world, and has produced some of the game’s most iconic figures from Johan Cruyff and Lionel Messi to Cristiano Ronaldo and Neymar.
In 2024–25, UEFA introduced new changes to the tournament structure and name, but the basic format of a group stage and a knockout round of sixteen has remained unchanged since its establishment in 1955-56. The field of thirty-two teams is divided into eight groups of four, with a randomized draw determining which clubs are assigned to each group. Each team plays the other three teams in its group twice, playing home and away. Teams earn points for winning, losing, and drawing; the team with the most points wins the group.
From the group phase, only the top two teams advance to the round of sixteen, which is contested much like other knockout rounds in major international soccer tournaments. The team with the higher cumulative score over both legs—a technique known as aggregate goals—advances. The ties are played over the course of several weeks in a home-and-away series, and a team advances to the next round when it wins its two matches. Unlike past tournament formats, there is no country protection, and teams from the same association can face each other in the first knockout round.