LONDON, United Kingdom (AFP) — Heavyweight champion Oleksandr Usyk has been ordered to start negotiations to defend his World Boxing Organization (WBO) heavyweight title against Joseph Parker.

The move that could end British fighter Daniel Dubois’ hopes of a rematch with the Ukrainian.

The WBO announced Thursday that Usyk, who also holds the World Boxing Council (WBC) and World Boxing Association (WBA) belts, has 30 days to “reach terms” for a mandatory title defense against New Zealand’s Parker or the governing body will call for purse bids.

Parker defended his WBO interim title in Riyadh last month with a second-round stoppage of Martin Bakole, a late replacement after Dubois withdrew because of illness.

Rather than reschedule his bout against Parker, International Boxing Federation (IBF) champion Dubois had hoped for a return clash with Usyk, who defeated the Briton by ninth-round knockout in August 2023.

Dubois reestablished himself in the heavyweight ranks with stoppage wins over Jarrell Miller and Filip Hrgovic before most recently knocking out compatriot Anthony Joshua, himself a former world champion, at Wembley in September to take his professional record to 22 wins, with two losses and 21 knockouts.

The 27-year-old Dubois was understood to be in talks to face Usyk in a fight that would see all four major world heavyweight titles up for grabs but the WBO’s announcement has complicated the picture in a sport where the lack of a single global governing body means there are often multiple world champions in the same weight class.

Usyk defeated Britain’s Tyson Fury in May 2024 to become the first undisputed world heavyweight champion in almost 25 years. But he vacated his IBF belt before the rematch, with Dubois elevated to full champion.

Former undisputed world cruiserweight champion Usyk, 38, extended his perfect professional record to 23 wins in as many bouts, with 14 stoppages, after defeating Fury in a rematch in December that meant he retained the unified WBC, WBA and WBO championships.

While Usyk was speaking immediately after being declared the winner by unanimous decision, Dubois entered the ring and interrupted the London 2012 gold medalist’s interview to demand a bout.