How the rating is computed

The rating is computed with the Elo system, like in chess. Before a game the system derives the expected result from the rating difference, and after the game it compares that with the actual score.

E is the expected share of wins. At equal ratings E = 0.5. Trailing by 200 points E ≈ 0.24 — an expected score of about 1:3.

Played better than expected — the rating goes up; worse — it goes down. So the score matters as much as the fact of a win.