The 12 teams -10 of which finished runners-up in their groups - were split into three four-team paths, each with its own semi-finals and final. Seeded teams were guaranteed a home game in the semi-finals.
The winning team from each path qualifies for the World Cup in Qatar, meaning Italy and Portugal cannot both reach the tournament.
Italy, who won the Euros earlier this year, and 2016 European champions Portugal will play their semi-final games at home against North Macedonia and Turkey, respectively.