LAS VEGAS – The Manny Pacquiao who knocked Juan Manuel Marquez down three times in the first round of a 2004 featherweight title fight hasn't existed for a long time.
That version of Pacquiao shot out of his corner like Cat Ballou, the 2,000-pound bull who is starring at the National Finals Rodeo down the street from the MGM Grand Garden where on Saturday, Pacquiao will face Marquez for a fourth and final time in one of the epic rivalries in boxing history.
The 2004 version of Pacquiao fought with an astonishing viciousness, blazing fast hands and a recklessness that quickly endeared him to millions.
Pacquiao was 25 then and not nearly as refined, as a boxer or as a man, as he is today. His physical skills were breathtaking, though, and he relied on hand and foot speed, his sheer athleticism and tenacity to carry him.
He's now a little more than a week from his 34th birthday. He's slower, not as aggressive and not nearly as reckless.
Neither is he beaming ear-to-ear like he did in those days, when he seemed to look at his world with a wide-eyed amazement.
This Pacquiao is much more grim, much more intense, much more businesslike.
One of his aides marveled at the change in his demeanor, noting, "I don't think I've ever seen him like this."
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After three extremely close fights with Marquez, of which he won two and drew one, Pacquiao is finally determined to settle the score the way he used to.
"He's gotten so big over the years and had so much going on in his life and so many responsibilities that boxing was just one of the things he had to do, not the only thing," trainer Freddie Roach told Yahoo! Sports.
"But he came to me after we signed this fight and he said, 'I'm going to be the old Manny.' He wants to do things like it was 2004 again. I don't think it sat too well with him that a lot of people, including a lot of you guys [in the media] felt like he lost those fights."
Pacquiao's natural inclination is to work. He still loves the day-to-day grind of preparing for a fight, hitting the mitts, pounding the bags, running great distances in solitude.
He loved it so much that he sometimes pushed himself beyond reasonable limits. Before he fought Marquez in 2011 and again prior to his June fight with Timothy Bradley, Roach had to put on the rein to ensure that Pacquiao saved his best for the ring.
And so, during the weeks of both the third Marquez fight and the Bradley fight, Roach forbade Pacquiao from running hard or pushing himself physically, having him taper off to be prepared to fight.
The results of those fights were mixed. The third Marquez fight was, from a fan's standpoint, a thriller. But in those two bouts, he won one against Marquez he should have lost and lost one to Bradley he should have won.
With Pacquiao begging him to go back to his days as a left-handed fireball, Roach gave in. When Pacquiao wanted to go to the track at UNLV and run earlier this week, Roach let him do it.
During his training camp, Pacquiao had scored three knockdowns in sparring, something that is a rarity for him because he doesn't often go hard after his sparring partners.
This, in many ways, is a fight that will define his career and he clearly not only wants to win it, but wants to win it decisively.
"I am always focused for my fights, but not like I am for this one," Pacquiao said.
And so, Pacquiao has adopted kind of a me-against-the-world attitude. You think he lost those bouts against Marquez? You believe he got a gift decision in the third fight because he's the more popular, well-heeled fighter? Well, Pacquiao has a point he wants to make to you.
He's on the backstretch of his career and he's wants to blaze to the finish like Secretariat at the 1973 Belmont.
"No doubts this time," Pacquiao said.
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It's going to be a tragic day for the sport when he's gone. He's been one of the game's most exciting fighters for more than a decade, but he, along with archrival Floyd Mayweather Jr., have kept it propped up from an attention standpoint over the last five years.
The theories on why he's yet to fight Mayweather are legion. Mayweather's followers have bought his shtick hook, line and sinker, and, incredibly, argue not about the purse that Mayweather wants for himself but the purse that Pacquiao wants.
Pacquiao fans have unreasonably painted Mayweather as a coward and accused him of being afraid.
The truth, as usual, lies somewhere in the murky middle.
Unquestionably, though, Pacquiao has helped drive boxing to a different audience. He was profiled on 60 Minutes, he's been featured on CNN, he appeared on the cover of Time.
He's sold out an arena again, with all 16,000 seats at the MGM gone, and brought media from all corners of the globe to see him.
He's not going to be around much longer.
It's time to appreciate him while he is, regardless of what version shows up Saturday.