Anthony "Rumble" Johnson knocked Glover Teixeira out with a stunning right uppercut, just 13 seconds into the fight.
Teixeira tried to stand with Johnson in the opening seconds and paid the price.
After the fight, Johnson was gracious in victory. He said that he and Teixeira showed that they could come out and fight without throwing water bottles or causing chaos in pre-fight promotional activities.
"Thank you for being a professional and showing the world what a professional athlete is supposed to be about," Johnson said.
Johnson is now in line to fight Daniel Cormier, in a rematch for the UFC light heavyweight championship.
Johnson called out Cormier, who was in the stands. Cormier raised his hands and embraced the invitation.
Johnson moves to 22-5 and Teixeira drops to 25-5.