How does Supercell calculate stars in the COC War League?
When you win a matchup, you get 10 stars in the overall league. So as an example, let's say you are clan A with 100 total stars playing clan B who had 90 total stars. Clan B beats you by 1 star, so they have 91, you have 100. Well because they won their matchup, they get a bonus of 10 stars, giving them 101, while you stay at 100.