Each tie is played over
two legs, with each team playing one leg at home. The team that has the higher aggregate score over the two legs progresses to the next round. In the event that aggregate scores finish level, the
away goals rule is applied, i.e., the team that scored more goals away from home over the two legs progresses. If away goals are also equal, then thirty minutes of
extra time are played, divided into two fifteen-minute halves. The away goals rule is again applied after extra time, i.e., if there are goals scored during extra time and the aggregate score is still level, the visiting team qualifies by virtue of more away goals scored. If no goals are scored during extra time, the tie is decided by
penalty shootout. In the draw for each round, teams are seeded based on their 2011
UEFA club coefficients, with the teams divided into seeded and unseeded pots. A seeded team is drawn against an unseeded team, with the order of legs in each tie decided randomly. Due to the limited time between matches, the draws for the second and third qualifying rounds take place before the results of the previous round are known. The seeding in each draw is carried out under the assumption that all of the highest-ranked clubs of the previous round are victorious. If a lower-ranked club is victorious, it simply takes the place of its defeated opponent in the next round. Prior to the draw, UEFA may form "groups" in accordance with the principles set by the Club Competitions Committee, but they are purely for convenience of the draw and do not resemble any real groupings in the sense of the competition, while ensuring that teams from the same association are not drawn against each other. ==Teams==