Four-division legend Nonito Donaire will battle Mexican Alejandro Santiago for the vacant World Boxing Council bantamweight throne, the Mexico-based governing body said.

Donaire was supposed to face off with Jason Moloney but the Australian opted to take another route as he is also ranked highly by another boxing body and assured of a title crack.

The WBC and all three other alphabet-sanctioning groups — World Boxing Association, World Boxing Organization and International Boxing Federation — were left without a champion after the undisputed Japanese titleholder Naoya Inoue decided to go up in weight in pursuit of a fourth world title in as many weight divisions.

The WBC vacancy is expected to be filled by late-May or early-June.

Donaire, 40, hasn't fought since being dealt a brutal second-round knockout by Inoue in Saitama last June.

Sporting a 42-7-0 win-loss-draw record with 28 knockouts, Donaire will attempt to enter his fourth reign as world bantamweight champion against Santiago, best remembered by Filipino fight fans as the off-beat Tijuana fighter who battled Jerwin Ancajas in a draw in September 2018 at the Oracle Arena in Oakland.

Since the Ancajas draw, Santiago, now 27, has won 11 of his last 12 fights for an overall mark of 27-3-5 with 14 knockouts.

As this developed, the WBC has also approved a title elimination match involving Filipino Reymart Gaballo and Thailand's Nawaphon Kaikanha with the winner facing the survivor of the Donaire-Santiago clash.

On paper, Donaire is the clear favorite versus Santiago but the odds might be closer than expected given Donaire's high mileage and Santiago's unorthodox stance and fighting ways.

Given all the factors involved, the outcome will be extremely hard to predict.