Light heavyweight contender Joe Smith Jr. had his jaw broken by Sullivan Barrera at the end of the first round or early in the second Saturday night, but continued to fight on through the full 10 rounds.

It was a feat reminiscent of Muhammad Ali’s fight with a broken jaw in his loss to Ken Norton in 1973.

Like Ali, Smith (23-2-0, 19 KOs) ultimately lost his battle against the talented Cuban Barrera (20-1-0, 14 KOs), a unanimous decision loss by scores of 96-93 and 97-92 twice. The fight was part of the undercard of the HBO-televised title fight between Miguel Berchelt and Takashi Miura at the Fabulous Forum in suburban Los Angeles.

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“We don’t know if it happened at the end of the first round or the beginning of the second,” Smith’s promoter, Joe DeGuardia, of Star Boxing, said by phone Monday night.

This is the second time that Smith, 27, has broken his jaw. The last time, according to DeGuardia, was in 2010 during the only other fight that Smith has lost in his career. It happened against Eddie Caminero, and ended with a fourth-round TKO loss for Smith, the only time he’s been stopped. That break, according to DeGuardia, was much worse than this one.

“That was a real terrible break,” DeGuardia said of the 2010 injury. “It broke on both sides, and it was literally hanging. It was a 6-to-8-hour operation and his mouth was wired shut for months.”

DeGuardia said that last week, on his last day of sparring before the fight, Smith hurt his jaw. “He went to the doctor and they took an X-ray and it didn’t show a break,” he said. “But it was bruised up and it hurt. During the fight when it happened, they pretty much knew it was the jaw when he was feeling pain. He was feeling pain throughout the whole fight really bad. He said he was trying to disguise it and hide it. I think once or twice the referee (Jack Reiss) went over because he noticed it.”

DeGuardia said Smith will be sent to Stony Brook University Hospital, where they originally did the operation in 2010. He said they will also re-examine the X-rays taken last week to see if a break might have been missed.

Smith, who has had some big wins recently, including knocking Bernard Hopkins out of the ring in Hopkins’ final fight, will be sidelined for months with the injury. The 2010 break took eight months to heal and kept Smith out of the ring for a year.

A Long Island, N.Y., native who works in construction as his day job, Smith Jr. showed his raw power by knocking down Barrera with a left hook in the first round. From the second round on, there was no shortage of heart as Smith continued to fight through what can only be described as a devastating and painful injury to a boxer.

“He showed true grit, that’s for sure,” DeGuardia said. “It’s the kind of thing you look for in a warrior.”

Barrera  outworked and outlanded Smith, connecting on 39{785f1b6326cdeb4275f63506ca40214b5c07db8f245df0cea7927e7aae5a72b6} of his punches (187 of 484), while Smith was only able to land 61 of 320 punches (19{785f1b6326cdeb4275f63506ca40214b5c07db8f245df0cea7927e7aae5a72b6}) overall. The edge in power punches went to Barrera 129-46.

But it’s obvious in hindsight that Smith went into protect mode after the jaw was broken.

“It’s disappointing, but he’ll be back,” DeGuardia said. “You’ve got to get it properly treated, and stay out and don’t do anything until you’re healed up.”

DeGuardia praised Barrera’s grit as well, getting up from the first-round knockdown: “He fought a good fight and did what he had to do to win.”