Robert vs. Rhaegar isn't in the books...is it? Vague description of how it ended(Bobby B and his signature hammer to the chest) but nothing detailed or anything.
There's really only 2 truly extended one on one fights I can think of, both of them duels. Viper/Mountain and Bronn/Old knight dude in the Eyrie. Oh and I guess Jaime/Brienne went on a while, though only Jaime was really going all out the whole time. Oh, Hound vs. Beric too I guess, more than I thought when I started. In general he keeps the 1 on 1 fights pretty brief, like I imagine they would be in reality. Areo Hotah kersplatting Arys Oakheart for example. Even Jon and Halfhand was pretty short if I remember it right(possible I do not).
Random derail, whatevs.