Once the play-offs have been completed, the 32 remaining clubs are drawn into eight groups of four in accordance with. Clubs from the same association cannot be drawn into the same group.
Each club plays one home and one away match against each other club in its group. A club does not play more than two home or two away matches in a row and each club plays one home match and one away match on the first and last two matchdays. Three points are awarded for a win, one for a draw, and none for a defeat.
The eight group winners qualify directly for the round of 16, while the eight runners-up qualify for the knockout round play-offs. The clubs that finish third and fourth in their group are eliminated.