Both are pretty past it at this point, so it's a toss up. Prime for prime, I have Mercer for sure. Mercer's biggest advantage is that heavy jab of his. I could see him busting Chisora up with it.
If Chisora is in the same form he was for his last few previous fights then Chisora wins for sure. Mercer after semi retiring after the Witherspoon fight never really did anything of note and was pretty much a spent force. Both a their best though ? I'd pick Mercer because he actually knew how to throw a jab unlike Chisora who just plods forward.
