The reality of the defeat set in quickly.
"I am here with the former champion," UFC TV analyst Joe Rogan said in starting his post-fight interview in the cage after the Milwaukee main event.
Henderson (19-3) offered a wry smile and mouthed "former champion," knowing it was a label he would have to live with. For how long is unknown.
A mature Henderson proved to be a gracious loser in that post-fight interview. Months later, he has clearly managed to keep the championship setback in perspective.
"I was able to come to terms, realize 'Hey, it sucks. That's life. A lot worse things can happen than losing tour world title,'" he said in an interview.
"But I was able to come to terms with it, accept it, be mature about it. Man up and move on."
A string of body kicks and a slick armbar some four minutes 31 seconds into the bout ended the reign of the champion seen by many as the UFC's fighter of the year in 2012, when he won the 155-pound title from Frankie Edgar, defended it in a rematch and then comprehensively defeated Nick Diaz.
The 30-year-old fighter, now the No. 1 contender in the division, returns to action Saturday at the United Center in Chicago against former Strikeforce title-holder Josh Thomson (20-5 with one no contest).
UFC president Dana White has said Thomson, ranked No. 4 among lightweight contenders, will get a title shot if he wins. But White, knowing Henderson has lost twice already to Pettis, was non-committal about what a Henderson win would mean.
Henderson, who fights out of Glendale, Ariz., wasted little time returning to the gym even if he had to initially baby the arm mangled in the armbar.
His constant goal is "to get one per cent better every single day. "There's whole lot of things you can get better at, improve on, day to day."
Henderson proved that at Dana College in Nebraska. He went 5-14 as a freshman wrestler but turned himself into a two-time NAIA all-American who was 34-5 as a senior.
Henderson had other things to attend to outside of the cage after the title loss, with a Jan. 1 wedding date (he had proposed to his fiancee in the cage after a previous win). The nuptials did not impact his training, however. He squeezed workouts around wedding duties like an appointment to taste chocolate cakes with his wife-to-be.
Tucking into pastries during a training camp doesn't help the weight cut. But Henderson saw a bigger picture.
"I fight quite a bit. It's not that big a deal. But you get married only once in your life so you've got to make sure that's a special, big moment, day of your life."
He stayed away from the gym on his wedding day.
The honeymoon comes after this fight, with Henderson looking to take an extended break — "as long as we can get away for."
Looking back, Henderson sees the Pettis armbar as a "split-second lapse in concentration."
"We all make mistakes ... Anthony Pettis was just good enough to capitalize on the mistakes that I made, locked in a real good armlock."
As he did after the fight, Henderson praised Pettis for the way he turned the screw on the submission hold until he had to tap.
Henderson said the loss had taught him that past successes, all the talk and hoopla "doesn't really matter. What matters is how you perform.
"I made a mistake and got caught."
Henderson said he never used to think much about "what ifs" when it came to his career. But he says a string of interviews changed that, when he was asked again and again what it would mean if he did this or beat that guy.
"Before early in my career, it was always just go out there and beat the next guy up. Whoever they put in front of me,just go beat him up. Everything else would take care of itself. You want more money? Go beat the next guy up, it will take care of itself. You want better sponsors? Go beat the next guy, it will take care of itself.
"So now I'm going to try and go back to that, go back to just going in there and beating the guy across the Octagon from me. Everything else will take care of itself. If I want another title shot, if I keep beating guys up, that will take care of itself."
"Right now that's Josh Thomson," he added. "That's all I'm concentrated on."
Pettis remains somewhere in the back of his mind, however. But again Henderson is philosophical.
"It would be that much sweeter, it would be that much tastier if when I get my belt back, it is against Pettis and he's the one I get my hand raised against. But if it's not him, (if) it doesn't happen to be, then no big deal. It won't be the worst thing to happen in my life."