1st phase: 4 groups. 2 paired groups of 10 teams featuring the traditional clubs qualified by historical ranking, and 2 paired groups of 12 teams with the remaining teams. The 2 groups pairs were treated equally as for qualifying criteria despite the weight of the first pair. Each team would only play the clubs of its paired group in home and away stages, thus not featuring real round-robin system. The champions of each stage would qualify as well the top 2 teams on overall performance over both stages. As such no teams played in this phase the teams of their own group.