Who would win Minerva McGonagall or Severus Snape?

Bellatrix Lestrange, hands down. She would just use all of the devastating dark arts spells that McGonagall would refuse to use

Personally I Disagree with that I think McGonagall would win due to her sheer skill and loathing for Bellatrix just because dark magic is used doesn't mean it is going to win, proven in deathly hallows when Harry defeats voldermort without using an unforgivable curse.

I don't know, however McGonagall might deside to use an Unforgivable as we know Harry does multiply occasions in DH and once in OotP.