Messerschmitt Bf-109G-6/R6

I think you are taking this too literally.The pilots in question were comparing the 109 to other similar fighters ie monoplane fighters and models that the 109 would likely come across in combat,ie,spitfires,mustangs,p47's etc.

 

I think Mark3's informants were correct in that the 109 could turn inside many of its opponents: IF it was a slow-speed battle, and IF the 109 pilot was good enough to use 10/10ths of the plane's potential. Two big "ifs". Allied pilots were trained NOT to get into a slow-speed turning battle with either the 109 or the Zero. As Joe Foss said of the Zero, "If you're in a turning battle with a single Zero, you're outnumbered!"

 

You hit the nail on the head there.Towards the latter stages of the war,the 109 was being flown by increasingly inexperienced pilots who could'nt fully exploit the 109's strengths.The aircraft itself remained a formidable design throught the conflict......fantastic fighting machine.

 

So you are saying late war opposing fighters rather than "all fighters". That sounds more accurate with Harold's further refinements I wouldn't contest it. My rule of thumb is that when someone says A is better than everything else they are either wrong or talking about a very narrow measurement space. It would be interesting to know how the 109 compared to the IJN and IJA fighters that also had a reputation for being maneuverable especially at slow speeds.