It’s decided in two steps: first, the third-place teams are ranked against each other, then FIFA uses a pre-set bracket map to assign the advancing teams to specific Round of 32 matchups.

How the ranking works

The 12 third-place teams are compared on:

  1. Points.
  2. Goal difference.
  3. Goals scored.
  4. Team conduct / fair play score.
  5. FIFA world ranking if they’re still tied.

How the matchup gets picked

Once the best eight third-place teams are known, their exact opponents are not drawn randomly. FIFA has a fixed list of possible bracket combinations, and the advancing third-place teams are slotted into those spots based on which groups they came from.

Simple example

So if a third-place team finishes well enough to qualify, it doesn’t automatically “pick” an opponent. Its opponent depends on the tournament’s pre-written bracket scenarios, which are filled in after the group stage ends.

Why it feels confusing

The tricky part is that the World Cup has many possible combinations, so the Round of 32 can’t be fully set until all groups are done. That’s why you’ll see live tables and matchup trackers during the final group games.

TL;DR: rank the third-place teams first, then place the qualifiers into FIFA’s preset knockout slots based on the groups they came from.