It escalated with a shoving match between the two New York City transplants at Friday's UFC 187 weigh-ins.
It reached a crescendo at the start of their middleweight showdown Saturday night at the MGM Grand Garden Arena. Before the fight, Hall (10-5) got in Natal's face, had to be sent back to his corner, and twice came back out to the center of the Octagon.
Then Natal opened the fight with a low kick that many considered intentional.
From there? Well, the built-up grudge match had more fizzle than sizzle. Natal took a split decision, taking two out of three 29-28 scores.
Hall got the best of things in the first round. Natal rushed wildly at Hall often, but never quite seemed able to find his range. Hall, for his part, answered with punishing kicks, including a pair of head kicks late in the round.
The second, though, likely belonged to Natal, as Hall reverted to the frustrating fighter who seems to have all the tools but never seems to put them all together. Natal scored a takedown early, and while Hall scored two slams late, the bulk of the round went to Natal.
The action slowed over the first four minutes of the third round. The crowd, which was red-hot at the start of the fight, turned on the fighters. But Natal seemed to have more urgency and initiated the bulk of the action.
Natal won his third consecutive fight, while Hall had a three-fight win streak snapped.