Maybe Law for round 1. But Zoro for round 2.
I usually would have said Zoro both rounds but... Law second round for sure. He doesnt have the skill (or at least that he has shown) of haki high enough to combat his room ability. He could probably block the regular strokes like smoker did but not the one that he used on Vergo.
@SpeedForceSpider: well back then laws powers werent so clear, and while law by logic was probably stronger, it was much easier to argue in zoros favor, get what i mean? and yes zoro is the #1 badass, but at this rate, laws a close 3rd or 4th xD
Pre time skip is unclear seeing as Law has barely any feats. So pre time skip I would go with Zoro but post time skip Law would stomp in my opinion. Too hax, after what I saw from him last chapter(killing Vergo and in the process cutting the island in half)I am convinced he is stronger than Luffy.