"Tyson. Hi, mybrother. Don't be afraid. I will not leave you alone."

Oleksandr Usyk kept it succinct and polite when asked by BBC Sport if he had a message for fellow heavyweight world champion Tyson Fury.

Fury, 35, is the WBC champion while Ukraine's Usyk, 37, holds the WBA, WBO and IBF belts.

A fight in Riyadh, Saudi Arabia, to crown the first undisputed heavyweight champion in the four-belt era has beenpushed backfrom 17 February to 18 May after Fury suffered a cut to an eye in training.

Usyk, who will now return toUkraine, has revealed he missed the birth of his second child on 28 January as he trained in his camp in Spain.

"I'm still happy - things happen, it's life," he said.

"I'm very happy because I now go to Ukraine. I see my two daughters and my wife. I go to my church and pray. A little bit of rest and back to my camp."

The bout has been rescheduled three times now. It was originally set for Wembley in April 2023 before negotiations failed at the last moment.

Fury's tougher-than-expected win against debutantFrancis Ngannou in October then delayed a proposed December bout.

Usyk's manager Alex Krassyuk says his fighter had to box before 18 May or face being stripped of the IBF belt.

If Fury withdraws from the contest again, Usyk will face Briton Anthony Joshua or IBF mandatory Filip Hrgovic, according to Krassyuk.

'I just smiled' - Usyk reaction to Fury withdrawal

Usyk invited a handful of media to a seaside hotel on the outskirts of Valencia on Tuesday, with reporters coming predominantly from Spain, the UnitedKingdom and Ukraine.

The event was arranged prior to Fury's eye injury and was originally meant to offer a look into Usyk's training camp for the undisputed title fight.

Rather than cancel or reschedule the event, the unified champion held a news conference and offered one-to-one interviews instead.

Usyk's team have been critical of Fury and questioned the legitimacy of the cut the Morecambe fighter picked up in sparring. Usyk's trainer Egis Klimassaid Fury was a coward.

But there were no such comments thrown towards 'The Gypsy King' during a news conferencewhere Usyk, Klimas and Krassyuk were all relatively subdued.

Speaking to BBC Sport, Usyk said he had just finished a sparring session when he was told by his team of Fury's injury.

"I just smiled," he added. "And said 'OK - I will finish my training and I will do my work stretching my back'."

Cutting a relaxed figure in yellow tinted sunglasses, Usyk was not as animated as he often is. Questions were relayed to him in Ukrainian by an interpreter but he replied in English.

The winner in Riyadh will become the first undisputed heavyweight champion since 1999 and the first in the four-belt era.

But Usyk said he is not focussed on whether Fury will be in the opposite corner.

"I don't think about it. It's versus Tyson or not versus Tyson," he said. "For me now it doesn't matter. I just want an undisputed fight." (BBC)