Sophie played Clay Valley as her third card, getting enough bricks to play Pyramids and win on turn four.
When stuff like this happens, I think the AI should give some sort of smack talk. Is there any possibility of programming in phrases each AI opponent can say depending on the situation? I'd love to see Le Marquis de Vrille remark upon it being unfair if begin playing with the Holy keyword set in your deck, or Grofgul complaining if you bring him down to one of a facility type.
Adding more flavor to the game is a really good thing if you want to branch this out to more players. I really enjoy these AI challenges from a flavor perspective.