I have a really easy way to beat night elves as undead! The southern most city of the night elves is really easy if you have the right tricks. All you need is the spearmaster, 2 speed, and 3 armor(that's what I had when I fought them). I did this on 60% diffuculty, and I don't think it works on any harder. Normally, Whirlers will kill you every time. However, with the auto spawn unit option on, you don't have to do anything. Just start the battle, and switch to spearmaster. You should win if you just do it in the same lane over and over again, while unleashing a charge once able to. It really worked!