There is a difference between the first round and the second round of the World Cup upset.

The first round of the World Cup is a group match, and the second round is a knockout match. Due to the large number of participating teams, FIFA divided the participating teams into several groups, with four teams in each group. Each team played against the other three teams once, and the two teams with the best results after the group match advanced to the second round.

After the draw, every two teams compete, the winner enters the third round and the loser is eliminated. From the second round until the champion is produced, it is a knockout.

The first round of the World Cup usually refers to the group match, that is, a single round match in which 32 teams allocate 4 places in each group, that is, each team plays for the first time (once).

The second round, also referred to as the group match, is the second game after each team finished the first round, which is the second game of each team.

The first round refers to the group competition (integral nature), the second round refers to the competition played by 32 participating 16 teams, the third round refers to the 1/4 finals of the top 8, and the fourth round refers to the top 4, that is, the semi-finals, and finally the champion.