LONDON • Ukrainian Oleksandr Usyk is more worried about his son's first days at school than stepping into the ring against world heavyweight champion Anthony Joshua in London on Saturday.

The Briton will be putting his World Boxing Association, International Boxing Federation, World Boxing Organisation (WBO) belts on the line in the fight at Tottenham Hotspur Stadium.

Both men won gold medals at the 2012 London Olympics, Joshua the champion in the super-heavyweight category and Usyk in heavyweight.

This will just be the undefeated Usyk's third pro fight at heavyweight and his opponent is of a different calibre to anyone he has faced but the 34-year-old (18-0 with 13 knockouts) has other things on his mind.

"At the moment, I don't think about Anthony Joshua," said the mandatory WBO challenger who flew into London on Monday.

"I don't think about what he will do, what he will use, how he will box. Right now, I think more about how my son feels at school because he has just started first grade and he really did not want to go."

While Joshua is the bookmaker's favourite, he told Sky Sports television he did not consider Usyk, the undisputed cruiserweight world champion, to be someone boxing above his preferred weight class.

"All boxers can move up in weight. Some feel better at the higher weight, they carry more power and feel fresher," said the 31-year-old, who has a professional record of 24 wins and one defeat.

He also commended Usyk for stepping out of comfort zone even as he revealed his intention was to "beat that confidence out" of him.

"When (Evander) Holyfield came up to heavyweight I think he had six fights at heavyweight before he fought for the championship belt," Joshua told the BBC.

"Usyk's fought two heavyweights. He's jumping in at the deep end early on. But good luck to him - he must believe in himself. He wants to be at the top end early.

"It's better to swim deep - get in there and get on with it - rather than tread water. You could still end up drowning... You might as well jump in the deep end and try to survive."

Should Joshua beat Usyk as expected and World Boxing Council champion Tyson Fury next month get past American Deontay Wilder to conclude their trilogy, it would likely set up a blockbuster "Battle of Britain" bout down the line.

Not since Lennox Lewis in 2002 has there been a unified heavyweight champion.

REUTERS