If Filipino champion Marlon Tapales beats Japanese "Monster" Naoya Inoue, then it's going to be boxing's biggest upset this year.

Negotiations are now underway for the undisputed super bantamweight title clash between the two boxers, who are expected to slug it out in November this year.

But it won't be an easy fight for Tapales, who won the WBA and IBF titles by outpointing Uzbekistan’s Murodjon Akhmadaliev in San Antonio, Texas last April.

"Talagang mabigat 'yung Naoya Inoue," said boxing analyst Atty. Ed Tolentino.

• Boxing: Marlon Tapales formalizes challenge vs Inoue

Tolentino said Tapales needs to go through the eye of a needle to hack out a split decision against Akhmadaliev.

"You go back to the last fight of Tapales. He was in trouble in the last two rounds of the fight, he was able to hang on. Pero iba 'yung Naoya Inoue," he said.

Inoue, already a four-division champion, demolished a previously unbeaten Stephen Fulton in eight rounds to win the WBC and WBO versions of the straps.

Tolentino also pointed out that the Japanese has improved leaps and bounds since his near-loss to Nonito Donaire two years ago.

"Ang chance ni Tapales dito is 'yung i-underestimate siya ni Naoya Inoue. 'Yung baka isipin ni Inoue, 'Walk over fight lang ito,'" he said.

• Boxing: Tapales seeks to unify super bantamweight titles

But rest assured, Tapales will get the biggest pay day of his career against Inoue.

"At the very least, he is assured of a very good pay day. Sigurado 'yan, maganda ang kikitain niya," said Tolentino.

"The Filipino fighter relishes being the underdog. What make a victory sweeter is if he pulls off the upset of the year."