I dont duel for XP on this world, ranked top 10 on world 1, here is just to rack up the wins and the cash to obtain the best gear possible at my level.
Beat guys worth over 150 XP to me, but also beat guys worth 7 XP, makes no difference as i get 0 XP off both as i have 0 motivation when duelling.
Like Billy Blaze said, the duelling ranks are a good indication on one front but are not always accurate in terms of the best dueller for their level.
On the other hand, it is only fair to say as Hefty said, unless you have duelled everybody, it would be hard to find out officially. My record on this world should speak for itself, but no doubt i will have people saying i just duel the weak, etc,etc. I duel for cash, not for the kudos, i dont attack workers though unless provoked lol, i do have some standards.