In the knockout phase, teams play against each other over a single match. If the match ends up as a draw, extra time will be played and if the match remains a draw a replay match is set at the home of the guest team which the extra time rule stands as well. If a winner doesn't occur after the replay match the winner emerges by a flip of a coin. The mechanism of the draws for each round is as follows:
In the draw for the round of 16, the eight top teams of each association are seeded and the eight clubs that passed the qualification round are unseeded. The seeded teams are drawn against the unseeded teams.
In the draws for the quarter-finals onwards, there are no seedings, and teams from the same group can be drawn against each other.
^Πάνος Μακρίδης-Ευάγγελος Φουντουκίδης, Αυτός είναι ο Ολυμπιακός • Η ένδοξη ιστορία του δημοφιλούς συλλόγου, έκδοση εφημ. ΑΘΛΗΤΙΚΗ ΗΧΩ, Athens 1957, p. 91 (in Greek)