BRAKPAN, South Africa – Hasim Rahman's knockout of Lennox Lewis did more than install a new heavyweight champion. It derailed perhaps the most lucrative fight in boxing history.

Rahman flattened Lewis with a stunning right hand near the end of the fifth round early Sunday to capture the WBC and IBF titles.

	Lennox Lewis couldn't recover in the fifth round, but said afterwards "He (Rahman) won't beat me twice."

"I kept my prayers going and did all my training. And I came up with one punch," Rahman said. "One punch."

That blow effectively killed any chance of a Lewis bout against Mike Tyson – potentially a $100 million showdown – happening anytime soon.

"No Lewis-Tyson! No Lewis-Tyson!" Rahman yelled in the ring after the fight.

Lewis-Tyson had been on hold because of a clash of TV contracts _ Lewis is with HBO, and Tyson with Showtime – and now might never happen after Lewis' stunning upset loss.

"There's no Mike Tyson if I don't get past Hasim Rahman, simple as that," Lewis said.

Rahman, a 28-year-old fighter from Baltimore, chased the champion across the ring and, with Lewis smiling defiantly at him, unleashed a right cross that caught the champion flush on the jaw and sent him sprawling to the canvas.

Lying on his back for several seconds, Lewis was unable to beat the count and, at 2:32 of the fifth round, the world of boxing had a new, totally unexpected, heavyweight champion.

The finish was eerily similar to Lewis' last loss, on Sept. 24, 1994, when Oliver McCall floored him with a right hand.

"I felt fine in there. I was going about my work nice and comfortably and there was no way Hasim Rahman could beat me," Lewis said. "This is just what happens in heavyweight boxing. He hit me with a good shot. That's the situation when you get two big guys in there with right hands."

Not long after the fight started at about 5:30 a.m. – the pre-dawn local time put the fight on U.S. TV at night – there were signs that an upset was in the cards, with Rahman (35-2) clipping Lewis on the chin in the second round.

Lewis seemed intent on ignoring his left jab, and instead concentrated on throwing big right hands.

In the third round, Lewis landed a left, followed by a left-right combination, but Rahman responded with a big right hand of his own.

Lewis (38-2-1) had Rahman in trouble early in the fourth but was rocked by a left hook and hundreds among the 5,500 in the crowd at Carnival City Casino began chanting "Hasim! Hasim!"

Lewis' stamina was questioned because he arrived in Johannesburg only two weeks before the fight, with little time to get used to the 5,200-foot altitude. That showed in the fifth round as he clearly began breathing heavily.

Rahman, throwing punches on the run, had Lewis backpedalling and the challenger ended the fight with the spectacular knockout punch.

"I told you all I was confident. Not one time since the fight was made was I nervous," said Rahman, who put himself in line for a much bigger payday than the reported $1.5 million he earned Sunday.

"He came out and tried to dictate the pace but I wouldn't let him. I never took an opponent serious before this. I felt like if I didn't train properly he would have the edge."

Lewis went into the bout at his heaviest weight ever – 253 pounds, 16 more than the challenger, who also surrendered 3 inches in height and 9 inches in reach.

While Rahman had been in South Africa for about a month to prepare for his title shot, Lewis was here half as long after taking time off to film the remake of "Ocean's Eleven" with Julia Roberts, George Clooney and Brad Pitt.

Lewis has a rematch clause in his contract.

"I definitely want the rematch," he said. "Hasim Rahman is the champ today. The second time around Hasim Rahman is going to go."