DZ
I was thinking in the low-level environment.
Guys I have talked to who flew MiG-21s and MiG-23s during CONSTANT PEG in the 1980s say that while the MiG-21F-13 could initially out-accelerate most types in a drag race, it would soon be left behind by the likes of the F-16, F-15, F/A-18 etc. As for the MiG-23BN/MS, they claimed it was untouchable in terms of raw speed and acceleration.
The fastest Blue Air type at the time was the F-model F-111 with the TF30-P100 motors, and the Flogger easily out accelerated them and had a higher top end speed.
One guy told me that he's had more than 850 knots from a Flogger on the deck, and that it had still been accelerating when he realised his speed and promptly raised the nose and simultaneously throttled back. This incident occurred when he had been making a stern conversion on two F-111s under GCI control; he'd started five miles behind them, but was seven miles in front of them by the time he popped back up for GCI to give him a new vector!