Nobody expected fury to win by UD. Winning by ko is not lucky but for an an extreme underdog it is the most likely way they would win.
Definitely its impressive but more shocking i think would still go to Rahman vs Lewis. I dont think anyone thought he would spark Lewis like he did
Rahman was more impressive in the fact he Knocked out Lennox with one shot. Fury just did enough to beat Wlad which was not very impressive at all. It was pretty boring to be honest.
It is more impressive because it is more difficult. Whenever there is a huge underdog, predictions will say "the favorite will win bar a lucky punch." They don't say "favorite will win bar a TOTALLY DOMINANT SHUTOUT DECISION". Looks cooler? Def. More impressive?lol.
Fury beating Klitschko was more impressive for me. Rahman caught an out of shape unmotivated Lewis with a lucky punch whilst being outboxed.