By Liam Napier

For better or worse, one punch can change a boxing career.

"I'm back," a jubilant Cameron said after reclaiming the WBO Asia Pacific and Oriental belts.

The importance of Cameron's killer overhand right, the hand he broke three times previously, in the fourth-round that appears to have ended Barrett's career cannot be understated.

"We left the metal plates in this time and it seems to be working,"

Cameron's manager Ken Reinsfield said of the dodgy hand.

Barrett may be past his prime but the 41-year-old was the first man to floor David Tua.

He also had two world title shots and has been in the ring with heavyweight champion Wladimir Klitschko, Hasim Rahman and David Haye.

Despite only suffering two defeats in 31 fights, a loss to the American would have crippled Cameron's desire and credibility. This emphatic, underdog upset did exactly the opposite.

As Barrett's eyes rolled back and his head lay on the canvas for over a minute, Cameron realised he had revived his career and opened the door to a serious payday.

"What it shows is what one punch can do to change a whole fight, your whole career,"  the humble Cameron said.

"David [Tua] did that to me. I did that to Barrett tonight. It shows how brutal this sport can be. It's not nice to be on the receiving end.

"Barrett is going to wake up with a sore head tomorrow, but his pride is going to be dented more. I know what that's like.

"It's not about how you fall but how you rise and comeback."

Barrett has now been floored 18 times in 47 fights but Cameron felt he had made a statement like no other.

"This proves that I'm worthy of being in the heavyweight division," he said.

"A lot of people have knocked him over but no-one has put him to sleep like that. It shows you what one punch can do. I don't know if I won the first round, but I won the second and third ... and definitely the fourth."

Nearly three years after his brutal second-round defeat to Tua, who is understood to be courting the services of training guru Lee Parore and on the verge of coming out of retirement, Cameron finally got to shed his inner baggage by fronting on the big stage.

"This has exercised a lot of demons for Shane," Reinsfield said.

"I'm so happy for him. He cops a lot of criticism because Tua did to him what he did to Barrett. No matter what we said, it kept coming. That proved tonight it can happen to anyone. One punch in a heavyweight division can change a career. It happened to any of the great fighters.

"Tonight, he did what David Tua couldn't do."

While a Tua rematch is the obvious next avenue, Reinsfield wasn't about to make any predictions and hinted at keeping the options open.

"David is coming back, good on him. At the moment we are not looking at David Tua. Last time he got a leg up on his career out of Shane.

"We'll see what comes up from this. There's a lot of other heavyweights that now might want to fight Shane, including the Klitschkos. Why not?"

After trash-talking at every opportunity in the lead-up to the fight, Barrett's dressing room was guarded with no-one allowed entry.

He was, however, spotted with a towel on his head, both hands over his face.

Barrett's manager, Stan Hoffman, indicated his client's boxing days were over.

"Monte's future is behind him. I will sit him down when we get to New York and tell him to finish," Hoffman said.

"Shane needs to have someone who can get him major fights. So far, no-one knows him anywhere but here. They've got to find a way to get it done.

"This will help. The truth is Monte is not a big name. He's been a good fighter and, as they say, is a gatekeeper. It's good that he beat him. Now, they need to make a plan."