Ruiz wears "a mask" according to Kevin Barry, who warned of his threat to Anthony Joshua

Andy Ruiz v Anthony Joshua Venue: Diriyah Arena, Saudi Arabia Date: Saturday, 7 December Coverage: Live BBC Radio 5 Live commentary with live text commentary on the BBC Sport website and app

"The two worst detectives working in New York!"

As BBC boxing correspondent Mike Costello and pundit Steve Bunce reflect on the June night that changed the boxing landscape, they curse the fact they didn't piece together clues to see it coming.

Kevin Barry did.

He said people were "kidding themselves" in writing Andy Ruiz Jr off before his fight with unbeaten world heavyweight champion Anthony Joshua.

Here Barry - trainer of former WBO heavyweight champion Joseph Parker - tells BBC Sport why he was influenced by his "history" with Ruiz, explains why the champion's style creates panic, and predicts who will win Saturday's rematch in Saudi Arabia.

'I've had to reinvent myself' - Joshua on Ruiz Jr rematch

'Ruiz hits harder than AJ despite mask'

Barry emphatically warned Ruiz could prove everyone wrong when he spoke at a news conference 24 hours before the underdog did just that.

The New Zealander was at New York's Madison Square Garden because Parker was joining forces with Joshua's promoter Eddie Hearn. But the journalists present had one thing on their minds - whether Briton Joshua would face Deontay Wilder after beating Ruiz.

"I had history with Andy," says Barry, the 1984 Olympic light-heavyweight silver medallist.

"In 2013 I was asked if I would train him. Had the opportunity not been so exciting with Parker, I probably would have.

"In the first year we ended up sparring Ruiz. The first time, Joseph looked at this overweight guy joking around in the ring and looked at me disbelieving and said: 'Are you serious?'

"Within the first 15 seconds Andy hit him about 20 times. On the way home, Joseph apologised to me."

Three years on, Parker beat Ruiz on points in Auckland to win the WBO world title. It remains Ruiz's only defeat.

Barry says: "Andy was on TV coming off the plane, an overweight, short guy. I spent two weeks trying to convince the public that this was a fight against one of the toughest, most battle-hardened fighters at heavyweight.

"You take the mask aside - and by mask I mean the extra weight - and you have a man who was a good amateur and a man I've watched chop down big guys time and again.

"I took Parker to fight Joshua in Cardiff in 2018, so I had a front-row insight into that too. Parker has told me the hardest he has ever been hit was by Ruiz.

"I kept thinking about that and Ruiz had just been written off. So I made my opinion known."

Barry (right) helped train Joseph Parker to a world heavyweight title in 2016

Panic, pressure and avoiding the same result

Barry was in the front row for the seven rounds during which Ruiz sent Joshua to the canvas four times.

As soon as the IBF, WBA and WBO belts were handed to Ruiz, conspiracy theories began to circulate about Joshua's health. His team have dismissed them as fiction.

"I said to Parker when Joshua was in the ring before the fight: 'Something isn't quite right,'" says Barry, 60. "His body language was different. He looked like someone who shouldn't really be in there."

Six months on, despite being the champion, Mexican-American Ruiz is again the underdog with the bookmakers.

Barry, who has trained fighters for almost three decades, believes the outcome may hinge on if the champion can again apply constant pressure. At 6ft 2in - though many think he is closer to 6ft - Ruiz must not allow Joshua the chance to make the most of his 6ft 6in frame.

He says: "The biggest adjustment for 'AJ' is dealing with Ruiz coming forward as he has not handled that well. Joshua likes to control and dictate. When that is taken away from him, he has shown a weakness.

"The big thing about controlling the pressure of Andy is you have to train yourself to embrace the pressure and not be restricted, depleted or panicked. Being pressed forces you to keep thinking, and that mental pressure will drain you every bit as fast as the physical pressure, if not more.

"To deal with it, Joshua must make the proper use of his height and reach. If he does the same as last time, the result will be the same."

Joshua has shared social media videos of him honing his footwork since losing to Ruiz. In recent interviews he has stressed he has prioritised working on his skills over other aspects of training.

"Dare I say it, he needs to be more like Wladimir Klitschko," says Barry, referring to the former world heavyweight champion.

"At 6ft 6in, you must use that jab. When you have so many attributes and strengths, you must use them. Don't gamble."

Raising his voice, he adds: "All he has to do is win seven of 12 rounds. I think he will realise - and he really needs to - that you don't have to win every fight by a knockout."

'I have been so happy with how everything changed' - Ruiz Jr

More than belts on the line

Barry says Joshua will have needed to work on his mentality after his defeat by Ruiz.

"You have to look at why you were knocked down four times and if you don't dissect it back to the root, you can never give yourself the mental confidence to move forward," he adds.

It is reported Joshua will earn a minimum of $85m (£66m) at Diriyah Arena. There is obvious reward but colossal risk - and not just for him.

Hearn has built a formidable stable of fighters, but Joshua is his biggest draw. DAZN - the streaming service Joshua is affiliated to in the US - has banked on his success. A second defeat would hurt both.

"The stakes could not be any higher for Joshua, his trainer Robert McCracken, for DAZN, and Eddie Hearn is under huge pressure," says Barry.

"It has all the makings of a classic in a country that has never seen a fight on this scale before. It does make you think back to fights like the 'Thrilla in Manila' and 'Rumble in the Jungle'."

So who wins this time?

Muhammad Ali pulled off a major upset against George Foreman at the 'Rumble' in Zaire in 1974. Foreman said he "lost something as a man" that night. So did Joshua at Madison Square Garden?

"Ruiz has the belts and everyone says once you become champion you're 10% better and I think that is a fair statement," says Barry.

"But I think Joshua will fight a totally different fight. When he had Ruiz down, all he had to do was take his time but he ran in with the wrong punches and put himself there to be hurt.

"This time we will see more poise. If he uses his skills and controls the pressure, I think Joshua wins the fight."

Ruiz shocked the world in June. But not Barry.

Now the man who warned we could see a new world champion in New York believes the belts will be changing hands again.