Xu wrested the 126-pound crown from Puerto Rico's Jesus Rojas in Houston, Texas, in January to become the third Chinese to win a pro world title, following Xiong and two-time Olympic gold medalist Zou Shiming (ex-WBO flyweight titleholder).

Kubo, a 5-foot-9 lefty, was far from an easy challenger, especially considering the 29-year-old's split decision win over compatriot and current No 1 contender Hiroshige Osawa in April 2018 in his first test after moving up to featherweight.

Xu attributed his convincing victory to his thorough preparations. Max Power Promotions sought out an ideal sparring partner for the champ, 22-year-old Filipino southpaw Joepher Montano, who matched Kubo in height, range and style.

"We have strong faith in Xu believing he has what it takes to beat a tough challenger in a quality fight," said Lu Xiaolong, CEO of Max Power. "The rise of Chinese pro boxing needs a victory like this to maintain the momentum and Xu delivered."

Xu, who earned the ring moniker Monster for his ferocious attacking style, now wants to unify the fragmented WBA title. While Xu holds the "regular" WBA featherweight title, Mexico's Leo Santa Cruz is currently the more prestigious "super" champion of the division.

"Santa Cruz has always been my target," Xu told the post-fight media conference. "I am looking forward to a WBA-title-unifying bout against him.

"I don't want to make any bold statement (concerning my next defense), because my fight always speaks for me. Now that I've proved I belong in the top of the division, I fear no one."