The draw of the qualifying round was held on 23 June 2017, 13:30 CEST, at the UEFA headquarters in Nyon, Switzerland. The 40 teams were allocated into four seeding positions based on their UEFA club coefficients at the beginning of the season. They were drawn into ten groups of four containing one team from each of the four seeding positions. First, the ten teams which were pre-selected as hosts were drawn from their own designated pot and allocated to their respective group as per their seeding positions. Next, the remaining 30 teams were drawn from their respective pot which were allocated according to their seeding positions. Based on the decision taken by the UEFA Emergency Panel at its meeting in Paris on 9 June 2016, teams from Serbia or Bosnia and Herzegovina would not be drawn against teams from Kosovo. Below were the 40 teams which participated in the qualifying round, with the ten teams which were pre-selected as hosts marked by .
Key to colours
Group winners and best runners-up advance to the round of 32
Format
In each group, teams played against each other in a round-robin mini-tournament at the pre-selected hosts. The ten group winners and the runners-up with the best record against the teams finishing first and third in their group advanced to the round of 32 to join the 21 teams which received a bye.
Tiebreakers
Teams were ranked according to points, and if tied on points, the following tiebreaking criteria were applied, in the order given, to determine the rankings :
Points in head-to-head matches among tied teams;
Goal difference in head-to-head matches among tied teams;
Goals scored in head-to-head matches among tied teams;
If more than two teams are tied, and after applying all head-to-head criteria above, a subset of teams are still tied, all head-to-head criteria above are reapplied exclusively to this subset of teams;
Goal difference in all group matches;
Goals scored in all group matches;
Penalty shoot-out if only two teams have the same number of points, and they met in the last round of the group and are tied after applying all criteria above ;
Disciplinary points ;
UEFA club coefficient.
To determine the best runner-up, the results against the teams in fourth place were discarded. The following criteria were applied :
Points;
Goal difference;
Goals scored;
Disciplinary points;
UEFA club coefficient.
Groups
The matches were played on 22, 25 and 28 August 2017. In each group, the schedule was as follows :
To determine the best second-placed team from the qualifying round which advanced to the knockout phase, only the results of the second-placed teams against the first and third-placed teams in their group were taken into account, while results against the fourth-placed team were not included. As a result, two matches played by each second-placed team counted for the purposes of determining the ranking.
