It’s almost hard to fathom.

Whether or not you give full weight to Manny Pacquiao’s career accomplishments, you must at least respect the fact that the Filipino star has been operating at a world-class level for a long time.

He won his first title during the Clinton presidency, became an HBO commodity while George W. Bush was in the White House and continued to remain relevant through two subsequent administrations.

In fact, he’s won at least one top-tier title fight in 12 separate calendar years since Jan. 1, 1998.

Most impressively, that run covers seven weight classes from 112 to 154 pounds.

But he’s got a chance to one-up himself later this month.

Pacquiao can add Joe Biden’s name to his burgeoning “I won while he was president” list on Aug. 21 when he faces Errol Spence Jr. for the Texan’s IBF and WBC championship belts in Las Vegas.

It’d also mark his 13th year with a title-fight win, placing him one behind ex-foe Floyd Mayweather Jr. – who had championship victories in 14 years from 1998 to 2015, missing only 2004, 2008, 2009 and 2010.

Such a long stretch of success naturally prompts debate about the best of the best moments.

Toward that end, here’s one man’s Tuesday morning view of his yearly title-fight peaks.

1998 – KO 8 Chatchai Sasakul, wins WBC flyweight title

Considering he won just one title fight in 1998, it’s an easy choice. But it’s remarkable to think anyone – from Pacquiao’s team to his family to the fighter himself – saw a two-plus decade run coming when this one ended on a Friday night in Thailand.

1999 – TKO 4 Gabriel Mira, defends WBC flyweight title

Again, just one title fight win in 1999 makes this a no-brainer selection. And considering Mira was venturing outside his native Mexico for the first time and had already lost seven fights in his career, the five-knockdown splattering job was no surprise.

2000 – No title fight wins

2001 – TKO 6 Lehlo Ledwaba, wins IBF junior featherweight title

Certainly among the most impressive coming-out parties in premium cable history. “Came out of nowhere,” HBO’s Jim Lampley said. “By the time Pacquaio had finished him off, in Round 6, we were well aware that if the world’s best junior featherweight was in the ring in Las Vegas that was the unknown Filipino, not the skilled South African to whom he had laid waste.”

2002 – TKO 2 Jorge Julio, defends IBF junior featherweight title

Go ahead, raise your hand if you remember that Pacquiao was on the undercard of the Lewis-Tyson heavyweight blockbuster at The Pyramid in Memphis. As a matter of fact, so were future champs Jeff Lacy and Joel Casamayor, along with future trainer Malik Scott. For his trouble, Julio lasted four minutes and nine seconds and was dropped twice along the way. He never won another fight.

2003 – TKO 3 Emmanuel Lucero, defends IBF junior featherweight title

OK, we’ve slipped through the technicality cracks here. Though Pacquiao’s quick erasure of Lucero came in his first appearance in Los Angeles, it pales in comparison to the defeat of Marco Antonio Barrera four months later in Texas. But the Barrera fight wasn’t a title fight in the eyes of any sanctioning group, so we’ll simply include Lampley’s recollection – “I was thinking, ‘Well, if anyone at this weight can beat him…’ Not even close.”

2004-07 – No title fight wins

2008 – TKO 9 David Diaz, wins WBC lightweight title

No, it’s not likely that history will remember Diaz as anything more than a stand-in champion. But he had gone 8-0-1 in his previous nine fights, including a decision over Pacquiao trilogy partner Erik Morales, before the Filipino conquered him and won a crown in his fourth weight class. Diaz was battered and bloodied from the early going and finally beaten to the floor in the ninth.

2009 – TKO 12 Miguel Cotto, wins WBO welterweight title

At this point, it almost looked as if no one on planet Earth could beat Pacquiao. It came 17 months after the Diaz pounding, and followed a non-title brutalizing of Oscar De La Hoya and a pit stop at 140 pounds to pick up the IBO’s belt from then-incumbent Ricky Hatton. But they paled in comparison to Cotto, who’d lost just once in 35 fights and was two defenses into his second reign at welterweight.

2010 – UD 12 Antonio Margarito, wins WBC super welterweight title

Like Cotto before him, the 150-pound catchweight certainly didn’t help a bigger, stronger Margarito, but it may have been the same result at any weight considering the ferocity Pacquiao showed. He won 33 of a possible 36 rounds across three scorecards and landed 411 power punches to the Mexican’s 135. “He was motivated to torture the cheater,” Lampley said, “and he did.”

2011 – UD 12 Shane Mosley, defends WBO welterweight title

Here’s a year with two big names, but no performances that’ll yield too many memories. The one-sided rout of a past-vintage “Sugar Shane” came six months ahead of Pacquiao’s third fight with Juan Manuel Marquez, which he won by a majority decision that only 12 percent of ringside media members agreed with. Of the remaining 88 percent, 46 had it for Marquez and 42 called it a draw.

2012-13 – No title fight wins

2014 – UD 12 Tim Bradley, wins WBO welterweight title

It was the second fight of one of the least celebrated high-profile trilogies and Pacquiao easily overrode the dubious decision from their first fight two years earlier, and convincingly announced his return to the big time after a shocking KO loss to Marquez. What few recall, however, is that Bradley entered the fight at No. 3 on Ring Magazine’s pound-for-pound list, while Pacquiao was four slots below at No. 7.

2015 – No title fight wins

2016 – UD 12 Jessie Vargas, wins WBO welterweight title

Once again, it’s likely that history will remember Vargas on roughly the same level as Diaz. Obviously a good fighter, but not near the level on which Pacquiao resided. Only judge Dave Moretti saw this one as a close contest, giving Pacquiao a one-point nod thanks to a knockdown in Round 2. The other two scorecards wound up with it 10-2 in his favor.

2017-18 – No title fight wins

2019 – SD 12 Keith Thurman, wins WBA welterweight title

Thurman had never lost. He’d been a champion for better than four years. And he arrived in the MGM Grand Garden Arena ring exactly 3,629 days – or nine years, 11 months, and six days, if you prefer – younger than his challenger. Still, it was the older man who set the tone with a first-round knockdown and outworked and out-landed the incumbent for most of the rest of the night.

2021 – To Be Determined?

“(Beating) Spence? There is absolutely zero logic in it. None,” Lampley said. 

“But Manny’s whole life has defied logic. I am the last person who would write him off. Spence is a gifted fighter, but does he have an X factor in his heart? He’d better. He is fighting the walking definition of an X factor.”

* * * * * * * * * *

This week’s title-fight schedule: 

Vacant IBF featherweight title – Brentwood, United Kingdom 

Kid Galahad (No. 1 IBF/No. 6 IWBR) vs. James Dickens (No. 3 IBF/No. 12 IWBR)

Galahad (27-1, 16 KO): Second title fight (0-1); Only loss (SD 12) came in IBF title shot in 2019

Dickens (30-3, 11 KO): Second title fight (0-1); Lost WBA title shot (TKO 2) at 122 pounds in 2016 

Fitzbitz says: It’s an intriguing rematch between two legit operators at 126. Galahad was the better man when they first met in 2013 (TKO 10) and should be again in the sequel. Galahad by decision (85/15)

Last week's picks: None 

2021 picks record: 26-7 (78.7 percent) 

Overall picks record: 1,182-382 (75.5 percent) 

NOTE: Fights previewed are only those involving a sanctioning body's full-fledged title-holder – no interim, diamond, silver, etc. Fights for WBA "world championships" are only included if no "super champion" exists in the weight class. 

Lyle Fitzsimmons has covered professional boxing since 1995 and written a weekly column for Boxing Scene since 2008. He is a full voting member of the Boxing Writers Association of America. Reach him at fitzbitz@msn.com or follow him on Twitter – @fitzbitz.