Usyk delivered an assured performance over 12 rounds last year to outpoint Joshua and win the WBO, WBA and IBF heavyweight titles.

It leaves Joshua in an unusual position for him, that of the challenger. He will have to walk first to the ring on Saturday night and Usyk, the new champion, made him wait for his arrival at the start of their press conference at the Shangri La hotel in Jeddah on Wednesday too.

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Joshua knows his place at the top of the heavyweight division depends on this fight. He insisted he cannot afford to lose.

"That's it. Must win," he said.

"I like the pressure," Joshua continued. "It's been tough. [Now] just get the job done. Instinct, stay focused, get the job done, God willing, victorious."

The Briton will summon all his competitive spirit to try to get his revenge.

"It's competition," he said of his motivation. "I've got goals I want to achieve in the ring on the night. That's competition with myself.

"You've got to have a competitive spirit."

Usyk is similarly inspired. "We were born to compete for life, for belts, for everything. The one who does not compete does not live," he said.

"All our lives are competition, for anything, for something, for somebody. That's why we are competing."

Joshua loomed over him in their final face-off but Usyk was undaunted. In fact, as Joshua departed the stage, the Ukrainian, with a smile on his face, burst into song.

Both fighters are ready. The 12 rounds they shared last year will make for a more closely contested fight in the rematch as they now know and understand each other's tactics.

"It's true," Usyk said. "We learned [about] each other in the last fight. He learned me. I learned him."

However, the Ukrainian intends to pick up where he left off - in the ascendancy.

"I don't think it's going to be a 'new' bout," he said. "The last bout will be continued for round 13, 14, 15, whatever it's going to last.

"We've had enough to study each other and this Saturday night it will be a great, great fight."

'We're ready to do it'

Both fighters can be counted on to be extraordinarily well prepared.

"Definitely was a great experience," Joshua's new trainer Robert Garcia said. "I think he's peaked at the right moment.

"The team did their job. [Anthony] did what he was supposed to do. We're ready, we're ready to do it. It was a challenge, obviously, coming off a loss and getting to do the game plan.

"At the end, the job was done. Anthony himself followed instruction and now the only thing in his mind is to become champion again."

Usyk's team gave an insight into the extremes the champion pushed himself to in camp.

"I've never seen anybody in 45 degrees heat ride a bicycle for 100 kilometres. I've never seen anybody swimming the day before the press conference in London for 10 kilometres in the pool for five hours. I've never seen anybody holding his breath under water for four minutes and 40 seconds, almost passing away," his manager Egis Klimas revealed. "Then I asked him, 'What's wrong with you?'

"He said, 'I know I have a trainer behind me, he's not going to let me drown. He's going to pull me out!'"

Both fighters go in with a win-at-all costs attitude. Which of them prevails can only be decided on Saturday night.

Anthony Joshua's huge heavyweight rematch against Oleksandr Usyk is on Saturday August 20, live on Sky Sports Box Office. Book Usyk vs Joshua 2 now!