guild challenge

If I am correct the opposition should only be able to play 10 games right? So how come they have played 15 games against my guild instead of just the normal 10?
They lost 5?
The guild challenges rules are : 10 teams per guild, 2 matches per team.
PierrotLL :

The guild challenges rules are : 10 teams per guild, 2 matches per team.


Until all 10 opponents have been defeated.