The invincible has fallen.
Once considered the ‘best pound per pound boxer in the world,’ Manny Pacquiao was knocked out cold by Mexican Juan Manuel Marquez. It was a decisive end to one of the most intense rivalries in modern day boxing. These two champions have met 3 previous times with controversy surrounding every match. This time Marquez put all gossip and innuendo to rest with a devastating right had that sent Pacquiao to the canvas.

Marquez rallied from a fifth-round knockdown and a bloody nose that had him trailing on all three scorecards. It all changed in the final second of the sixth round. Desperate for victory, Marquez landed a fierce right hand that electrified the the sold-out crowd of the pro-Marquez MGM Grand Garden Arena. Before Saturday Pacquiao won two narrow decisions after a draw in their first meeting.

Pacquiao was knocked down in the third round, the first time that happened since 2003 against Serikzhan Yeshmagambetov. Late in the sixth round, with Pacquiao moving forward while throwing a soft right, “I hit under his guard and got in a right hand,” Marquez said. “I knew Manny could knock me out at any time, I threw the perfect punch.”

Pacquiao fell face first onto the canvas and was out for several minutes as his cornermen – and wife – rushed furiously to his side to bring him back to consciousness.

“I feel so, so happy that the referee raised my hand,” Marquez said. “This was thanks to the work I did, the result of the training.”

Asked about his interest in a fifth fight, Marquez (55-6-1, 40 KOs) said, “I know in the future I will rest and celebrate. I’m thinking more about the celebration than who I’m fighting next.”

Pacquiao said in the ring afterward that he too will rest, but plans to fight again. Asked specifically about Marquez being his next opponent, Pacquiao said, “Why not?”It was a stunning scene and certainly brought to a close Pacquiao’s incredible run that saw him win world titles in a record eight weight classes, win a congressional seat in his native Philippines and become a global star.

“I was careless. He’s not an easy opponent,” Pacquiao said. “I did my best, but that’s boxing. That’s sports. I thought I got him in the last couple of rounds, but I got hit by a strong punch. I never expected that punch.”

“I never thought he was going to beat me,” Marquez said. “I was coming strong. He came at me good, but I was strong. I was not going to lose that fight.”

Going into the sixth round, Pacquiao, 33, was ahead 47-46 on all three scorecards, but that wouldn’t make a difference. Marquez, his nose a bloody mess — although it was announced after the fight that is was not broken — landed a huge right hand over a jab from Pacquiao that missed. It connected on Pacquiao’s jaw and he crumpled near the ropes, face down, just feet from former Republican presidential nominee Mitt Romney and his wife, Ann, who sat ringside.

“We always work on that punch,” said Marquez, 39, a four-division champion. “The change in rhythm was important. We knew he was going to come out aggressive, so we had a fight plan that was more technique. We were able to capitalize on it.

When Pacquiao regained his senses, he and Marquez embraced. “You are a great fighter,” Marquez told Pacquiao.

HBO will replay the fight on Saturday night (9:30 ET).on Saturday night at the MGM Grand Garden Arena.