SPOILER.........
Yoda loses ya, but there are several factors I believe that led to this. First, he is old. Very, very VERY old at the time of the duel. He dies of natural causes 25 years later at like 900, so basically it is like a guy who will die at 90 of natural causes, fighting for the heavy weight title at 88. Secondly, he is distrought over the death of all the younglings and Jedi's in the temple. That has to be weighing on his mind a bit. Third, he has never seen a true sith before, and the fighting style is something he has never encountered. Yoda trained Dooku, so that is something totally different. Lasly, from what I have read in the book, Palpy uses some very unorthodoxed moves, such as tossing senate pads and stuff that yoda isn't use to.
All this combined I think made him lose, but if they fought again the next day, I think Yoda might come out on top. He would adapt, and fight differently, and probably more agressively. Also, he's the man, so he has to be the best in my mind