In Rudel's autobiography, Stuka Pilot, he discusses being pusued by a Russian Fighter at low level. The fighter crashed, wether shot down by his gunner, or caught in his turbulance in stall/turn. According to Rudel this caused a STRONG reaction on the Russian Radio frequency, and it was later determined that a top russian ace had been lost. This was further discussed here.
http://www.elknet.pl/acestory/shesta/shesta.htm
Not a 100% indication, but suggestive.
Rob