The group stage featured 32 teams: the 22 automatic qualifiers and the 10 winners of the play-off round (five through the Champions Route, five through the League Route).[1]
The teams were drawn into eight groups of four, and played each other home-and-away in a round-robin format. The matchdays were 13–14 September, 27–28 September, 18–19 October, 1–2 November, 22–23 November, and 6–7 December 2011.[2]
Teams were seeded into four pots[5] based on their 2011 UEFA club coefficients.[6] The title holders, Barcelona, were automatically seeded into Pot 1. Pot 1 held teams ranked 1–9, Pot 2 held teams ranked 10–24, Pot 3 held teams ranked 31–83, while Pot 4 held teams ranked 86–200 and unranked teams.
For the group stage draw, teams from the same national association cannot be drawn against each other. Moreover, the draw was controlled for teams from the same association in order to split the teams evenly into the two sets of groups (A–D, E–H) for maximum television coverage.
The fixtures were decided after the draw. On each matchday, four groups played their matches on Tuesday, while the other four groups played their matches on Wednesday, with the two sets of groups (A–D, E–H) alternating between each matchday. There are other restrictions, e.g., teams from the same city (e.g. Milan and Internazionale, which also share a stadium) do not play at home on the same matchday (UEFA tries to avoid teams from the same city playing at home on the same day or on consecutive days), and Russian teams do not play at home on the last matchday due to cold weather.
Tie-breaking criteria
If two or more teams were equal on points on completion of the group matches, the following criteria would be applied to determine the rankings:[3]
higher number of points obtained in the group matches played among the teams in question;
superior goal difference from the group matches played among the teams in question;
higher number of goals scored in the group matches played among the teams in question;
higher number of goals scored away from home in the group matches played among the teams in question;
If, after applying criteria 1) to 4) to several teams, two teams still have an equal ranking, the criteria 1) to 4) will be reapplied to determine the ranking of these teams;
superior goal difference from all group matches played;
higher number of goals scored from all group matches played;
higher number of coefficient points accumulated by the club in question, as well as its association, over the previous five seasons.
Groups
Times are CET/CEST,[note 1] as listed by UEFA (local times are in parentheses).
Note: In 1991–92, the competition was still known as the European Cup, but is included as it was the first to use a group stage format. In that season and 1992–93, there was no knockout phase between the group stage and final.