I don't know about that Mace vs Sidious duel...
To me they seemed equal. I don't know who would have won if Anakin had not intervened but I believe when Palpatine sensed Anakin coming, he deliberatly "lost" the duel. I don't claim he would have won otherwise, but especially that scene where Palpatine rolls around on the floor, totally helpless, makes me think he lost on purpose, to twist Anakin to the dark side.
Oh, and Anakin would not stand a chance in single combat against either Sidious or Mace.