I got first-shot opportunities on occasion flying an F-15E against an F-16 when the viper driver sailed on past riding his AOA limiter, while I was free to spike the AOA deep into the "bad" part of the lift/drag chart, giving me a shot while he was still trying to slow down enough to use his turn rate and radius advantages.
I've also flown an F-15E (the big motor variant) and accelerated during an 8G 180 deg turn at low altitude. If you're talented enough to ride the best sustained turn AOA instead of stupidly automatically spiking the AOA past best L/D, even a pure delta design like the mirage has a hell of a sustained turn, like that pilot was writing about when comparing the mirage to the F-16. The trick is to fight your best fight against your opponent's worst fight. In an F-15, I could on occasion exploit the F-16's AOA limiter by using my ability to swing the nose around and decelerate inside his turn circle faster than the viper could react, and get off a first shot. Not always, and not even most of the time because the viper can turn up its own bunghole. But that was my best fight against his worst fight.
Assuming I was dumb enough to get within visual range of the little bastages anyhow... A talented F-15E crew could usually keep SA on 2-4 vipers as they wormed their way to the merge, picking them off one by one with high Pk shots before they got within 10 miles. Its hard for even a viper to defend against a well timed no-lock heater in the face as he pitches hot, and thanks to *gadgets* I could often accurately cue weapons long before they could see me.
I can easily see a mirage sustaining very high Gs at lower altitudes, as long as the pilot kept it at or below his best sustained turn AOA. The delta wing only has a drag spike if you keep pulling the AOA up, and modern high lift devices like drooping leading edges and flaperons combined with fly-by-wire and relaxed stability are very effective at improving the lift/drag curves of even a pure delta design.