For the record, Maul elbows Qui Gon in mid combat and then sabered him in the stomach while he was reeling. A reasonable move in combat, but still underhanded.
I still have to see Grievious to see just how good he is, but I still think, unless he's something short of incredible (Which I wouldn't doubt, since the prequel emphasis is on flash and pizzazz) Qui Gon would still have a reasonable chance to win.