After losing two and drawing one in three fights he had a right to believe he won, the bigger and stronger version of Marquez left no doubt this time around.
He concluded one of the year's best fights in stunningly brutal fashion, catching Pacquiao on the chin with a perfectly placed counter right hand, knocking the Filipino superstar out cold at 2:59 of the sixth round before an arena packed with his delirious fans.
It was the same right hand that Marquez landed repeatedly in their first three fights, shots that did little damage to Pacquiao. But after a year of building his body with conditioning coach Angel Guillermo "Memo" Heredia, Marquez had the zip he needed on his fastball to get the job done.
"We knew he was going to come out aggressive, so we had a fight plan that was more technique and we were able to capitalize on it," said Marquez, who broke his nose from a Pacquiao left.
As Pacquiao lay prone on the mat and Marquez and his fans celebrated, somewhere, Floyd Mayweather Jr. had to be kicking himself. The world's top boxer failed to sign a fight with Pacquiao that would have been the richest bout of all-time, haggling over seemingly minor issues with so much money at stake.
While it's not out of the question that Mayweather and Pacquiao could still fight, the bout will never have the kind of lustre it had when they were 1-2 in the rankings and both seemingly invincible.
Mayweather's one-time close friend, hip hop star Curtis "50 Cent" Jackson, knew as referee Kenny Bayless attended to Pacquiao that it was equivalent to flushing millions down the drain.
"That was a lot of money [going away]," he said.
The knockout also will be sure to raise numerous questions about how Marquez got so much bigger. Heredia is an admitted steroids dealer whose testimony during the Bay Area Laboratory Co-Operative case put track coach Trevor Graham in jail.
Marquez defiantly insisted all week that his work was natural, and he didn't address it on Saturday.
Rather, he was in the mood for a celebration after the biggest win of a sensational career. Marquez has been among the world's elite fighters for at least the past 15 years, but he's been forced to take a backseat, first to Mexican stars such as Marco Antonio Barrera and Erik Morales and later to Pacquiao.
Few fighters were as skilled and technically sound, but he didn't capture the imagination of the fans the way his rivals did.
But on Saturday, when he ended a sensational back-and-forth battle in which both men had been hurt and hit the canvas, they were jubilantly on his side.
The fighters were true to their pre-fight promises to attack. Pacquiao made an adjustment and was able to keep his lead foot on the outside of Marquez's lead foot. As a result, Pacquiao was able to rake Marquez with a series of hard straight lefts.
When Marquez went down in the fifth round, it was the fifth time in the four fights Pacquiao had decked him.
This time, though, there was a difference. Marquez had the ability to blunt Pacquiao's attack with power of his own, which he lacked the first three fights.
He floored Pacquiao in the third with a right hand and wobbled him several other times.
And even though Pacquiao was ahead on the scorecards – all three judges had it 47-46 for Pacquiao – Marquez was always confident.
"I never thought he was going to beat me," Marquez said. "I was coming strong. He connected with me hard, he got me good, but I was falling. But I was ready to push hard through the later rounds."
Pacquiao didn't show for the post-fight news conference. He walked out of the arena under his own power, but was taken to a local hospital for a CAT scan. The scan came back negative.
In the ring after the fight, he said simply, "I got hit with a punch I didn't see."
Pacquiao seemed to have Marquez reeling as the sixth was winding down. He missed a right hand and Marquez delivered the shot that landed right on the button.
"Manny was fighting a good fight and he ran into one," promoter Bob Arum said. "No excuses."
And also, no big payday for a fight with Mayweather. Arum said fans would still want to see a Pacquiao-Mayweather fight, given how exciting Pacquiao was on Saturday, and that's probably true.
It won't, however, be nearly the same. The stakes won't be the nearly as high and the potential revenue the fight generates will be a fraction of what it could have been.
Marquez, though, cared about none of that. After such a bruising battle, he didn't want to consider any possibility about boxing, including a fight with Mayweather.
"As far as my future, what is coming, I don't want to even think about it," Marquez said. "I want to go home and get some rest and celebrate with my family. I don't want to even think about who I might fight next."
There is no word on what Pacquiao may do next, but the sad news is that the dreams of a mega-fight with Mayweather fizzled away as Pacquiao laid knocked out face first on the mat.
That one punch ended eight years of frustration for one man while destroying the dream of a fight that should have been made but was not.
- Sports & Recreation