The opponent who gave Naoya Inoue his most difficult fight slightly favors Stephen Fulton to upset the Japanese superstar in their upcoming showdown.

Nonito Donaire considers Fulton’s size advantage a significant factor in their 12-round fight for Fulton’s WBC and WBO 122-pound championships. Philadelphia’s Fulton (21-0, 8 KOs) has fought at or near the junior featherweight limit of 122 pounds throughout his eight-year professional career, whereas Inoue will make his debut in that division when he faces Fulton on July 25 at Ariake Arena in Tokyo.

“With Inoue going up in weight and Fulton being the champion, you know, I have to give a slight edge [to] Fulton because Inoue has never fought anybody like Fulton,” Donaire told BoxingScene.com. “And Fulton is the champion, so I just have to give a slight edge to Fulton. I think Fulton is hungry and he is excited for this fight because [Inoue is] a name that will get him to be noticed in the boxing world like Inoue is, in terms of notoriety and stuff like that. That’s something that Fulton is looking to have.”

Fulton stands almost 5-foot-7, nearly two inches taller than the 5-foot-5 Inoue.

The 30-year-old Inoue (24-0, 21 KOs), a three-weight world champion, began his career in the 108-pound division. Inoue’s last nine fights were contested within the bantamweight division, in which he became the first fully unified 118-pound champion of boxing’s four-belt era.

If anyone understands the challenges that come with moving up in weight it is Donaire. “The Filipino Flash” fought as high as the featherweight maximum of 126 pounds during his 21-year, 49-fight professional career.

Jamaica’s Nicholas Walters (then 24-0) dropped Donaire twice and knocked out the five-division champion in the sixth round of their featherweight fight in October 2014 at StubHub Center in Carson, California. Donaire also lost a 12-round unanimous decision to Northern Ireland’s Carl Frampton (then 24-1) in an April 2018 featherweight bout before Donaire dropped back down two weight classes and revived his career by going on another successful run at bantamweight.

The 40-year-old Donaire will attempt to bounce back July 29 from his devastating second-round knockout loss to Inoue in their June 2022 rematch at Saitama Super Arena in Saitama, Japan. Las Vegas’ Donaire (42-7, 28 KOs) is scheduled to fight for the unclaimed WBC bantamweight belt he lost to Inoue in a 12-round fight against Mexico’s Alexandro Santiago (27-3-5, 14 KOs) on the Showtime Pay-Per-View portion of the Errol Spence Jr.-Terence Crawford undercard at T-Mobile Arena in Las Vegas ($84.99; 8 p.m. EDT; 5 p.m. PDT).

Inoue gave up his IBF, WBA, WBC and WBO bantamweight titles to move up four pounds for the Fulton fight. Fulton-Inoue will be streamed by ESPN+ in the United States four days before Donaire returns to the ring.

“Inoue’s gonna do what he does, but I think that’s a great fight,” said Donaire, who lost a 12-round unanimous decision to Inoue in their first fight in November 2019. “You know, it’s one of those fights people have to see.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.