Guillermo Rigondeaux (left) slips a jab from Ricardo Cordoba en route to out-pointing the former 122-pound titleholder on the Manny Pacquiao-Antonio Margarito undercard. The split-decision victory earned Rigondeaux a No. 5 ranking in THE RING's junior featherweight ratings. Photo / Chris Farina-Top Rank

Only Manny Pacquiao could beat Antonio Margarito in a junior middleweight fight and subsequently supplant Floyd Mayweather Jr. atop the welterweight ratings.

Pacquiao’s dominating victory over Margarito for a vacant 154-pound belt was impressive but it wasn’t enough to merit a spot in THE RING’s junior middleweight ratings, according to the magazine’s editorial board.

The reason is simple: Margarito, unranked by THE RING going into Saturday’s fight, is not a world-class junior middleweight. The former welterweight beltholder, who was knocked out by Shane Mosley in his last meaningful fight, is unaccomplished at 154 pounds.

However, the editorial board viewed Pacquiao’s ability to dominate Margarito even though he was well under the 150-pound catch weight as an accomplishment that enhanced his standing in the welterweight division, where THE RING ranked him No. 2, behind Floyd Mayweather Jr., prior to the Margarito fight.

Pacquiao (52-3-2, 38 knockouts), whose weight for Margarito (144.6 pounds) was light for a welterweight contest let alone a junior middleweight bout, was advanced to the No. 1 spot in the welterweight rankings, displacing Mayweather.

“Due to the fact that Manny Pacquiao is more active and weighed in as a welterweight for the Antonio Margarito victory, he has overtaken Floyd Mayweather,” said Nigel Collins, Editor-in-Chief of THE RING. “The WBC junior middleweight belt at stake will look nice in Manny’s trophy case, but really doesn’t mean very much, especially as Margarito was unranked by THE RING going into the fight.”

RING RATINGS UPDATE

WELTERWEIGHTS:

Mayweather (No. 1 last week) and Pacquiao (No. 2 last week) trade places.

JUNIOR FEATHERWEIGHTS:

Previously unranked Guillermo Rigondeaux debuts at No. 5 after beating Ricardo Cordoba (No. 5 last week). Cordoba slips to No. 6, which pushes down everybody ranked last week one spot each and forces out Masaaki Serie (No. 10 last week).

“While Guillermo Rigondeaux’s win over Ricardo Cordoba was far from aesthetically pleasing, he did beat a Top-10 junior featherweight,” said Collins. “Therefore, he deserves to be rewarded for the victory.”