You get a bonus for having a better deck
You get a bonus for winning with more cards (6 cards win is worth less than a 9 cards win)
You get a bonus for playing someone the first time I think?

You also get base points according to the opponent's average.

If you win against 1 guy worth 80 pts a win and then with 1 guy worth 120 pts a win, you are now worth 100 pts yourself - because your average is 100. If you win against 2 guys worth 120 each after that, your average is now 110.
Etc

The more you win against quality players, the more points you gain in one go.
Most I've had was 134 I think, some are pulling 140+ points on average and I'm yet to figure out how.