How Uefa's 'Swiss system' might work
First used in a Zurich chess tournament over a century ago, the 'Swiss system' has rarely featured in elite sport - but that could change if Uefa agrees a radical shake-up of the Champions League group stages.
The new system would see 32 or 36 teams placed in one league, each playing 10 games against teams seeded in four different pots. The top 16 teams would then advance to the knockout stages.
The format is yet to be agreed and finalised, but it is thought that the teams ranked from 17th to 24th would drop into the Europa League. Positions in the table may also affect seeding for the last-16, with the top-ranked side playing the team in 16th place, and so on.
https://www.theguardian.com/football/2021/apr/16/champions-league-new-36-team-format-set-for-uefa-approval-on-monday