It had been too long since I had played Warcraft 3, so I decided it was time for an old-school AI battle. Since AI is not that smart I always like to play against more than normally possible.
During this game though, I had noticed a truly fatal AI ‘think’-flaw.
As I was fighting many enemies at once, I noticed that once you attack one AI, all his allies come charging in also.
This brought me to the idea to lure one enemy in range of my towers and defeating his allies as they come charging. What worked very nice also, was that as soon as one of my towers was hit, this triggered all my allies to come and aid me (thinking my base was under attack).
Fighting from a fortified position with many archers and a hero that would level up very fast since she was constant in battle, showed me I could win against steep odds.
It took a few games, but eventually I managed to defeat 7 AI-opponents (normal difficulty) with only 3 AI allies.