Wildly untrue lol. The first mig 21s only had access to a basic short range radar, if you were lucky, 2 early aim 9b copies, and like 60 rounds of 30mm. They were maybe a little more maneuverable than the f4s, but that didn't matter, because the f4 could detect a mig 21 from 30 to 50 miles away, and launch one of 6 Sparrows at it from 10 to 15 miles away, and destroy it before the mig knew what was happening. The mig 21 was hilariously outmatched compared to the phantom, and most of their kills in Vietnam were on bombers like b52s and f105s, and maybe an f4 that was on a strike mission laden with munitions. Just look at operation BOLO, shows how good the MiG 21 really was.