2011 AFC Champions League knockout stage

A total of 16 teams, 8 from West Asia and 8 from East Asia, competed in the 2011 AFC Champions League knockout stage. They included the 8 group winners and the 8 group runners-up from the group stage.

Each round of this single-elimination tournament was played over one or two matches. In the round of 16, each tie was played in one match, hosted by the winners of each group against the runners-up of another group. In the quarter-finals and semi-finals, each tie was played over two legs on a home-and-away basis. The final was hosted by one of the finalists, decided by draw. The away goals rule (for two-legged ties), extra time (away goals do not apply in extra time) and penalty shootout would be used to decide the winner if necessary.^[1]

The matchups for the round of 16 were decided prior to the group stage draw.^[2] After the completion of the round of 16, the draw for the quarter-finals, semi-finals, and final was held in Kuala Lumpur, Malaysia on 7 June 2011.^[3] In this draw, the "country protection" rule was applied: if there are exactly two clubs from the same country, they may not face each other in the quarter-finals; however, if there are more than two clubs from the same country, they may face each other in the quarter-finals.