Yeah, I'm reading and the only real way Ace wins is if he managed to fill Law's entire room with fire.
But then you have to take into account that the only confirmed haki Ace has is CoC which isn't all that effective against people of the same level. Plus since Law has CoA confirmed, he could put down ace imo.
People think Ace was so far above everyone that no one could have closed the gap while he was dead for two years. I'd beg to differ, especially when going up against someone as haxed as Law. If there's another animal on the battle field, Law can just swich their personalities and win that easy!