George Foreman's crushing right uppercut connected for the first time in Round 1 and, suddenly, the heavyweight champion of the world was on the canvas. At ringside, the shocking sight sent Howard Cosell into a frenzy.
"Down goes Frazah! Down goes Frazah! Down goes Frazah!" Cosell screamed into his ABC microphone.
Across the ring, Foreman was thinking one thing: Please don't let Joe Frazier get up.
"I saw him get up and I said to myself 'Oh boy, he's going to get me now,' " Foreman recalled Tuesday during a telephone interview. "You didn't want him getting up, and you really didn't want him getting up mad."
Get up Frazier did, only to go down again and again. Six times in all before the bell sounded to end the second.
Yet there he was still, out on his feet but still upright and ready for more. Frazier wasn't going to surrender his world heavyweight title until the referee mercifully put an end to the carnage in Jamaica.
"Joe Frazier wouldn't back away from King Kong," Foreman said. "Joe Frazier was one brave man."
Brave enough to take on the fearsome and much bigger Foreman in a fight he seemed destined to lose. Brave enough to hand Muhammad Ali his first loss and then almost fight to the death with him in the Philippines.
But that's what Frazier was. An undersized warrior who didn't know how to back down. A fighter to the core.
Understand that, and you understood Joe Frazier.
He kept getting up when Foreman knocked him down. He kept trying to fight Ali even though one eye was swollen shut and he couldn't see out of the other.
And he kept fighting for his rightful place in history until his death Monday night in Philadelphia at the age of 67.
"His pride and dignity made him fight to the end," promoter Don King said. "Joe never forgave Muhammad Ali for what he did to him, but Joe Frazier proved that he wasn't only a great fighter but a great man."
I spent some time talking to Frazier this year as he reminisced about his career and his life. The 40th anniversary of the Fight of the Century was looming, and Frazier was more than happy to talk about a memorable night long past.
No one at Madison Square Garden that night, it seemed, wanted him to beat Muhammad Ali. Not the fans who scraped together enough money to get a cheap seat in the rafters, and certainly not the celebrities and various rogues of the night who dressed in their finest to parade around ringside before the bout.
Frank Sinatra shot pictures for Life magazine from ringside. Barbra Streisand and Bill Cosby watched from seats just a few steps away.
They saw Frazier do what no man had done before - beat the great Ali. If that wasn't enough, he knocked Ali down in the 15th round with one of his classic left hooks to seal the deal.
"I can't go nowhere where it's not mentioned," Frazier said. "That was the greatest thing that ever happened in my life."
He fought Ali the way he fought everyone, with his chin planted on his opponent's shoulder, because that was the only way he could fight. Frazier barely stood 5-foot-10, never weighed more than 205 or so. He wasn't going to beat people with his physical skills, so he figured out a way to keep relentless pressure on until he could find a way to land a left hook that surely was one of the most beautiful punches in boxing.
It didn't work against Foreman because Foreman was too big, too powerful. Ali found a way to beat him in their final two fights, too, including a fight so epic that boxing people simply shake their heads when asked what happened at the Thrilla in Manila.
Ali later would say it was the closest thing he ever knew to death. Though blinded by his swollen eyes, Frazier still tried to fight the 15th round against one of the greatest fighters ever.
The bitterness toward Ali that Frazier carried throughout the rest of his life was especially rooted in that fight. Ali called him a gorilla, an Uncle Tom. When Frazier returned home, his children asked why the other kids at school were saying the same thing.
"Joe could never forgive him for that," King said over the phone. "But you have to know the times, the race struggle in America. Joe couldn't understand why some of the blacks looked at him with disdain and then extolled Muhammad Ali. But Smokin' Joe was an integral part of history. That fight changed things for a lot of people. It changed the respect paid when people would look at other people of color."
That fight changed things for Frazier, too. Neither he nor Ali were ever the same after the brutal bout, and Frazier would have only one more meaningful fight, a second knockout loss to Foreman.
"Joe Frazier, sharp as a razor," he told them.
Ali put out a statement saying he would always remember Frazier with respect and admiration, something Frazier surely would have scoffed at.
In the end, he'll go down as one of the great heavyweights ever, a man who fought hard in Ali's shadow, then fought even harder to get out of it.
"All he wanted to do was beat up Muhammad Ali one more time," Foreman said. "Maybe someday in heaven he'll have a chance to do it."