Unless the UFC has new rules I am unaware of - Josh is a complete idiot in the ring. Two or three times he had a hold of Diego's foot, with Diego not kicking or trying to pull away. A first year grappler would have ankle locked and won in 10 seconds (I remember Ken Shamrock getting beat with one of these back in the early days of the UFC). Or even some type of knee lock. Josh showed his utter lack of understanding/execution of finishing moves. That is what lost him the fight.
Diego could not sink in the guillotine - which he almost got at the very end of round two I believe before time ran out. Josh was able to shoot and throw Diego to the mat as easily as he did with Chris in their fight. The difference again was Josh having NO ground game or idea on how to finish.
Deigo might be the more well rounded fighter, but American wrestling showed again how well it trains fighters to shoot and takedown. It is just a matter of the fighter not being a complete putz and having some type of finishing move (i.e. ground & pound, simple submission). Diego of course was talking trash like he easily handled the fight, which made the split decision all the funnier.