[1] The teams were drawn into eight groups of four, and played each other home-and-away in a round-robin format.
[2] The draw for the group stage was held on 30 August 2012, 17:45 CEST (UTC+2), at Grimaldi Forum, Monaco.
Teams were seeded into four pots based on their 2012 UEFA club coefficients.
There were other restrictions, e.g., teams from the same city (e.g. Manchester United and Manchester City) in general did 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 did not play at home on the last matchday due to cold weather.
If two or more teams are equal on points on completion of the group matches, the following criteria are applied to determine the rankings:[2] The matchdays were 18–19 September, 2–3 October, 23–24 October, 6–7 November, 20–21 November, and 4–5 December 2012.