Willy, cause he killed William Wallace (aka. Mel Gibson, aka. Mad Max (who could easily kill Wolverne, cause he has guns and stuff)) in a head on fight. don't believe me? here goes:
http://www.grudge-match.com/History/willy-wallace.shtml
see? and if ya don't believe me that William Wallace could take on Wolverine, see what he did to SNAKE PLISSKEN!!!
http://www.grudge-match.com/History/max-snake.shtml
see? and Solid Snake (no, not SolidSnakeAss) was based off of Snake Plissken, and now don't tell me that Solid Snake couldn't take on Wolverine. Maybe not head-on, but still, in a maze, Snake would win, but, I digress.
Willie, simple, he defeated Mad Max, who defeated Snake Plissken, who is actually Solid Snake as well, who could kill Wolverine with relative ease.