Anthony Joshua's rise to superstardom is little surprise to author of his new book

Anthony Joshua’s exciting world heavyweight title victory over Wladimir Klitschko raised a lot of eyebrows – but the author of a book dedicated to AJ’s incredible rise was only slightly shocked.

John Dennen is a journalist for Boxing News, the longest-running boxing magazine still in publication, dating back to 1909. And prior to the titanic title clash at Wembley Stadium this past Saturday, he penned Joshua, a front-line chronicle of the Olympic gold medalist’s journey from the amateurs to his maiden world championship as a pro.

Dennen’s close professional bond with Joshua forged over the years led to him predicting a round-eight KO win for the Londoner – and he wasn’t very far off.

“Klitschko was much better than I thought he was going to be, so Joshua deserves even more credit,” Dennen told Yahoo Sport UK.

“I had a feeling he could deliver his power pretty late on in a fight. There’s been a suggestion that he’s too musclebound, or too heavy and therefore his stamina could be exhausted in the championship rounds. But he’s always been an extremely diligent trainer, a lot of that strength training seems to me to be pretty functional.

“Joshua’s got genuine, explosive power.

“Even though no one had managed to particularly trouble him as a pro before Wlad, as an amateur he showed he could push himself through pain and tiredness when he was up against it. I knew he had heart.

“And Klitschko, for all his great talents, doesn’t have the greatest punch resistance on planet Earth.”

Dennen traded his usual ringside seat and post-fight press conference wristband to go as a fan, affording him the ultimate fight night experience at the culmination of Joshua’s rise. And he doesn’t regret it for one second.

“The occasion was unforgettable, though the experience was different to what I’m used to,” he explained.

“When you’re reporting you’re taking notes, doing a live blog at the same time as watching the fight, it’s kind of intense. But just watching you could get totally absorbed in the event.”

The win over ‘Dr. Steelhammer’ will be the ‘jumping-off point’ for many a casual sports fan who didn’t know much about Joshua before Wembley.

And that’s exactly who Dennen feels his book speaks to most, with its detailed documentation of everything up until that point. Everything that makes Joshua the figure he is today.

He said: “The idea of this book was to write about all the stuff I’ve been lucky enough to witness, seeing someone in these random amateur bouts, going from boxing in a school sports hall in Dagenham to reaching the top of the sport a few years later.

“The road from novice boxing through elite international competition and the Olympics was pretty dramatic in itself, then he became a star as a professional.

“I had a feeling that just getting the Klitschko fight put him on a whole new level, and every fight from now on will surely be massive.

“We’ve all seen or know what happened against Klitschko but this is my account of following how he got there, the making of a champion. The world will be watching everything that’s happening now, but this book covers what you might have missed.

“It was also a great way to write about the sport as a whole as well. It’s rare for a writer to get to follow someone all the way from the amateurs to a world heavyweight title and that was the story I wanted to tell.”

Joshua’s reputation as a ‘gentleman assassin’ has helped accelerate his career to the point where mainstream comparisons are being made to David Beckham, circa his breakthrough wonder goal against Wimbledon for Manchester United.

Dennen still fondly remembers seeing the two sides of AJ for the very first time.

He told me: “The first time I saw him box it was in his first ABAs, I think we’d spoken on the phone before though.

“Anyway he came looming out of his corner, staring down his opponent and battered him.

“He was always a powerhouse. I was frightened for his opponent. But then getting to know him it became clear very quickly he just wasn’t like that outside the ropes.”

John continued: “He does enjoy fighting but when the bout is done he’s genuinely a really likeable person.

“And he’s great for any sportswriter to write about, he thinks about what he says, he’s interesting. Plus scoring spectacular knockouts for fun adds to the appeal.

A combination of promoter Eddie Hearn’s ultra-confident hype for Joshua – he boldly declared his then-newest signing would unify the heavyweight division before Anthony had even made his pro debut – and what can only be described as ‘Post Audley Harrison Traumatic Syndrome’ means many British fight fans are reluctant to get too emotionally invested in any domestic prospect.

When Joshua quickly steamrolled his way through his first 18 opponents, many claimed AJ remained untested. When he reacted to the test of being knocked down for the first time by the strongest opponent available on the biggest stage in British boxing history, a few critics nonetheless remained.

“There have been successful British super-heavyweights in the Olympics, who had a big build up going pro and just didn’t manage live up to those expectations,” said Dennen. “So you can understand that the public or the boxing public were going to wait for Joshua to prove a few things before getting too carried away.

“But unlike some of his predecessors, Joshua had achieved great things as amateur in record time, he was a novice taking on and beating seasoned career Olympians.

“While his skills caught up with the competition he was making do with athleticism, heart and determination.

“To go from taking up the sport to winning an Olympic gold medal in only four years, that’s remarkable. That alone was a huge accomplishment and that suggested he had even more potential to get even better.

“I think that’s why Matchroom and so many other promoters around world were so keen to sign him. He proved at the amateur World championships, let alone the Olympics, that he could well be the kind of star the heavyweight division was waiting for.”

Until Joshua’s next fight is formally announced, Dennen will be back on the beat covering pros and amateurs across the globe.

That will likely include former Joshua opponent Dillian Whyte’s headline encounter at London’s O2 Arena on June 3 against Mariusz Wach. Perhaps now, 18 months later, Whyte has forgiven Dennen for the role he played in his old rivalry with AJ returning to boiling point ahead of their fiery battle.

Dennen explained: “Their beef stretched back to the amateurs but just when it was settling down I blundered in writing a feature in Boxing News comparing their accomplishments and sort of dismissing it as rivalry.

“Anyway, it had the opposite effect. Dillian took huge exception either to what I wrote or what Joshua said in the article and it all rapidly escalated.

“It became their first pay-per-view event, and Joshua singled me out at a press conference as the instigator in front of the nation’s media, which will probably remain my enduring claim to fame.”

Joshua by John Dennen, published by Yellow Jersey Press, is available in bookstores now. You can also purchase online by clicking here.