Pettis, who bested Henderson when the two met for the WEC lightweight title, did the same for the UFC belt, earning a first round submission win.
“I’ll be back,” said Henderson, who had already bested Frankie Edgar, Nate Diaz and Gilbert Melendez in defenses. “Don’t worry about that; no question.”
Henderson was in control for the most part before Pettis grabbed his arm during an exchange on the ground. “Showtime” locked up the armbar and, as Henderson said, “did a good job of twisting it, turning it the right direction.”
Pettis stated he heard a pop and Henderson had his arm under his shirt, telling Joe Rogan “my arm’s killing me, dog.”
The loss was the first in eight UFC fights for Henderson, dropping his overall record to 19-3.