Israeli AF vs. Soviet Migs?

Just saw an episode of Wings, in which they described an incident during 1970 when there was alot of tensions and sporatic fighting between the Israeli AF and Egyptian AF. The story was that the Soviet advisors were chastising the Egyptian pilots on their fighting ability. Finally the Russians got their chance to fly against the Israeli’s and five Russian Mig 21 pilots were promptly shot down! Is there any truth to this story, It was told by an Israeli General, who was told about this by Mubarrak, who was an Egyptian fighter pilot.