By Keith Idec

If Nonito Donaire performs as well as he anticipates against Wilfredo Vazquez Jr. on Saturday night, “The Filipino Flash” knows who he wants to fight next.

Donaire expects to challenge Japan’s Toshiaki Nishioka in what would be a 122-pound championship unification fight sometime in the spring. Newly crowned WBA super bantamweight champion Guillermo Rigondeaux has repeatedly called out Donaire since the unbeaten Cuban won that title from Rico Ramos on Jan. 20, but Donaire considers Nishioka the most imposing opponent he could encounter in his new weight class.

“I want to unify the belts, so there’s a possibility of me fighting all the champions,” Donaire said. “But first things first. We want to look for another title and the guy I’ve been aiming for is Nishioka.”

Nishioka (39-4-3, 24 KOs), a 35-year-old southpaw, defeated Mexico’s Rafael Marquez (40-7, 36 KOs) by unanimous decision in his last fight, a 12-rounder Oct. 1 in Las Vegas.

That marked Nishioka’s seventh defense of the WBC super bantamweight title he first won on an interim basis in September 2008. Nishioka also has won 16 straight fights since he dropped a 12-round unanimous decision to Thailand’s Veeraphol Sahaprom in a WBC bantamweight title fight nearly eight years ago.

“I think he’s a great fighter,” Donaire, 29, said. “He’s the most complicated fighter to fight in this weight class. I think that he has the height [an inch taller than Donaire], he has the weight, and he’s a southpaw that will make it difficult for any fighter. He’s the most challenging fight for me in this weight class.”

Donaire (27-1, 18 KOs) — a former flyweight, super flyweight and bantamweight champion from San Leandro, Calif. — must first defeat Puerto Rico’s Vazquez (21-1-1, 18 KOs) in a 12-round fight for the vacant WBO super bantamweight title Vazquez lost to Jorge Arce on May 7 in Las Vegas. Donaire versus Vazquez will kick off an HBO “World Championship Boxing” doubleheader from Alamodome in San Antonio that’ll match Mexicans Julio Cesar Chavez Jr. (44-0-1, 31 KOs) and Marco Antonio Rubio (53-5-1, 46 KOs) in the 12-round middleweight main event.

“He’s good,” Donaire said of Vazquez. “I think that he has good power and decent speed. We respect him as a fighter, but I’ve got to go out there and do what I need to do. In terms of overall skills, I think I have the advantage.”

Keith Idec covers boxing for The Record and Herald News, of Woodland Park, N.J., and BoxingScene.com.