Champions League brings fans around the world a showcase of elite football that combines high-level strategy and tactical sophistication with drama, unpredictability and excitement. Its long-standing history adds to the prestige of the competition, while major advertising and sponsorship deals provide significant financial incentives for teams who qualify. It also serves as a barometer of the strength and depth of European soccer, with the tournament a major factor in attracting players, coaches and managers to the continent and rewarding clubs for their domestic success.

The modern era of the competition began in 1992, with A.C. Milan under Fabio Capello and later Carlo Ancelotti becoming one of the early dominant forces. Their 1994 and 2005 finals, both decided by penalties, remain among the most enduring moments of the event, with Milan demonstrating a style of play that combined solid defense and devastating attack.

Following some experimentation with different group stages, the competition returned to a single group stage and a knockout round of sixteen in 2003-04. During this phase, thirty-two qualified teams were placed into eight groups of four teams; a randomized draw determined the group-stage matchups, and a system of coefficients was used to help ensure competitive balance.

Teams earned three points for a win, two for a tie and no points for a loss; the top team in each group advanced to the round of sixteen. The next four highest ranked teams competed in a playoff round to determine the remaining eight spots in the round of sixteen.