It's hard to measure what success looks like against Jon Jones. The man has been fighting professionally since 2008, and no one has legitimately beaten him.
If we're being honest, though, the most recent attempts to halt Jones' perfection -- failed title bids by Alexander Gustafsson (December) and Anthony Smith (March) -- were downright disappointing.
Gustafsson (18-5) took Jones to the brink of defeat in a 2013 title fight, but in their highly anticipated rematch at UFC 232, he managed to land only 22 strikes. And Smith (31-14), who is known as one of the scrappiest, most unbreakable athletes in the UFC, inexplicably froze against Jones.