Grievous would slaughter jinn (for being a fathead with all the prophecy junk and bringing about the destruction of the jedi order), yoda would execute dooku, and then Grievous would become yoda's new padawan.(Grievous is not dooku's apprentice because he can't use the force and there can only be two sith atta time)
He's one of the best and, quite frankly, his technique sucks. I think that was an overstatement from a dubious author or source. I mean, Qui-Gon doesn't have a chance in hell against ROTS Obi-Wan, someone with 20 years less experience then him, nor against Yoda, Mace, or (I will daresay) ROTS Anakin.
The amusing and decidedly overzealous pro-Dooku ramblings above notwithstanding, why did you bump this thread? Assuming that he is waging battle without sentimental attachments and redemption for Dooku in mind (ie, the mentality he has regarding the Sith Lord after the debacle on Vjun), he will comfortably waste his former protege. Qui-Gon versus Grievous would be interesting, I think. Not that it matters, because if Qui-Gon doesn't win -- Yoda will come on over and manhandle Grievous.
Yoda and Qui-Gon (but mostly Yoda) win.