 Matches in the qualifying, play-off, and knockout rounds could also be played on Tuesdays or Wednesdays instead of the regular Thursdays due to scheduling conflicts.In the qualifying rounds and the play-off round, teams were divided into seeded and unseeded teams based on their 2016 UEFA club coefficients, and then drawn into two-legged home-and-away ties.Teams from the same association could not be drawn against each other.