Sosulin (13-0, 7 KOs) is ranked No. 1 by the WBA at 154 pounds, a pivotal position that’s earned him a designation as a mandatory challenger against unified champion Xander Zayas.

The 29-year-old Sosulin made another statement Thursday by stopping Victor Nagbe inside eight rounds while headlining the IBA Pro 15 show in Saint Petersburg, Russia.

Sosulin came into the matchup following a career-best decision win against former title challenger Magomed Kurbanov in July. Sosulin was installed as the WBA’s No. 1 challenger in December.

IBA director Al Siesta understands that Zayas has bigger fish to fry in the division, but still maintains that Sosulin deserves the shot.

“Sosulin and Zayas will have an incredible fight and one of them will score a stoppage – I’m just not sure who,” Siesta told The Ring. “Stylistically, it's a gripping fight. Zayas is a great fighter and there is a reason he's a unified champion. But Sosulin will shine once he gets the opportunity to step into the elite and world-level stage.

“Pavel comes from the traditional Russian school of boxing but has a relentless, aggressive and bullish Mexican style. He never gives in and never gives up, and hunts his opponents down. We're going to try to keep him active with a fight every three months until his mandatory opportunity against Zayas comes through.”

Complicating matters even more for Sosulin within the WBA is that Jaron Ennis became the interim champion during his division debut in October after stopping Uisma Lima in one round.

Zayas (23-0, 13 KOs) took the WBA title away from Abass Baraou after beating him by split decision in January.

In recent weeks, Zayas, The Ring’s No. 3-ranked fighter at 154 pounds and also the WBO beltholder, has been entertaining the idea of fighting Ennis and IBF champion Josh Kelly.