George Lucas himself stated that Windu won the duel, Darth Sidious then started to feign utter loss of power, when really Mace Windu was losing the grip on his lightsaber and would've been killed regardless (I think he was actually testing Windu to see how long Windu could hold on for), then he continued the feint until he forced Anakin to disarm and/or kill Windu, Anakin believed the feint so when Sidious killed him, he was taken utterly by surprise, so yes in short, Windu kicked Sidious' *** in the duel.
Really? I'm not trying to dismiss your answer, I like it, but I think I've heard, or read, that Sidious purposely withdrew from that 1 on 1 battle in order to better turn Anakin, to make Windu seem like the bad guy for striking down a defenseless opponent.
Did Sidious really lose, or did he sense Anakin's arrival and planned to turn him at that moment? Even without the saber he wasn't defenseless.