Actually, my mage can hold his own against almost anybody. He's won every type of character before (except pure SR monks since you can't dispel the SR w/ mords or whatever).
The point is some ppl in mage vs. mage duels exploit the lack of the "Improved Combat Casting" feat, and run close to you and cast a spell. But I'd understand if it's by accident. It happens sometimes.
I don't know the difference between pure mage duelers vs battle mages. My mage build is supposedly a 'pure' mage (as I have no PM or RDD levels), but he has 77 AC (and no auto-still). Tis pretty good. Vs. archers, I'd use improved invisibilty + warding, and hope they don't get crits. Vs. weapon masters, they have slightly worse AB, and my fortitude save is 49 so I'm almost impossible to be dev critted.
Only problem now is that instead of Auto-Still, I'm Auto-quickened. Should I change it to Auto-still? Or how about Auto-Silent?