Oleksandr Usyk has fired an early warning at his heavyweight rival Tyson Fury on Instagram as the pair met at the launch press conference for their rematch on Wednesday evening.

Usyk and Fury faced each other in a modern-day classic back in May, with the Ukrainian emerging victorious via split decision to become the undisputed heavyweight champion of the world again.

They will meet again on December 21 in Riyadh, Saudi Arabia, and went head to head to promote the event in London.

Before taking to the stage, Usyk posted a seven-word message on Instagram that read: ‘I will not leave you alone. Never’.

Usyk had a similar message before their first fight and was a man of his word as he pressed the action from the opening bell.

He scored a knockdown in the ninth round after landing a barrage of punches that ultimately turned the contest in his favour, and is confident of getting his hand raised again.

Usyk kept his cards close to his chest on Wednesday night, but did attend the press conference in a black suit clutching a mystery briefcase.

He was asked what was in the briefcase, and eventually opened it before heading over to Fury with a photo in his hand.

It proved to be an image of Usyk landing a huge left hand on Fury in their first fight, and he managed to convince the Gypsy King to sign it, drawing laughs from the assembled media.

Reflecting on how he plans to get a different result in their rematch, Fury said: ‘I’m just looking forward to a fantastic fight. Oleksandr won the last fight fair and square. It was a very close fight, only a point in it. A little bit more focus, a little bit less complacency and I will be victorious.’

He then referred to his previous record in rematches, adding: ‘My rematches with people always end one way.