As part of a trial that started in the 2009–10 UEFA Europa League, two extra officials – one behind each goal – were used in all matches of the competition from the play-off round.

[2] Chelsea's caretaker manager Roberto Di Matteo led the club to win their first Champions League title after beating Bayern Munich 4–3 on penalties in the final.

Associations are allocated places according to their 2010 UEFA country coefficients, which takes into account their performance in European competitions from 2005–06 to 2009–10.

To compensate:[6] The labels in the parentheses show how each team qualified for the place of its starting round:[7][8] All draws held at UEFA headquarters in Nyon, Switzerland unless stated otherwise.

HJK's 10–0 win over Bangor City in the second leg broke the record for the largest margin of victory in the current Champions League format.

The losing teams in both sections entered the play-off round of the 2011–12 UEFA Europa League.

The losing teams in both sections entered the group stage of the 2011–12 UEFA Europa League.

[19] Eighteen UEFA member associations are represented in this group stage: England and Spain by four clubs, Italy, Germany and France by three, Russia and Portugal by two, while eleven associations are represented by one club, which are all domestic champions except Trabzonspor, which replaced Fenerbahçe due to match-fixing allegations.

In the knockout phase, teams play against each other over two legs on a home-and-away basis, except for the one-match final.