Boxing guru Monty Betham says the title bout was marred by over-officiating in Joshua's favour.
It wasn't to be for Joseph Parker.
The Kiwi heavyweight lost his world heavyweight unification bout by unanimous decision, but still impressed after becoming the first man to go the distance with Anthony Joshua.
Joshua added Parker's WBO strap to his WBA and IBF titles, and moved within one belt of becoming the first undisputed champion since Lennox Lewis in 2000.
Deontay Wilder holds the other main heavyweight belt, the WBC's, and could meet Joshua before the end of this year.
Here's how the media from around the world reacted to the biggest fight in New Zealand's history:
"AJ was taken the distance for the first time in his professional life as he added yet another world heavyweight title to his unifying roll call of honours. Four down and one to go.
Joshua used Parker's capacity for absorbing heavy punishment to his exercise his improving skills as well as his considerable power.
There was experience gained under the roof in Cardiff's Principality Stadium which will be valuable when our WBA, IBF, IBO and now WBA title holder goes after Wilder in his bid to become the first undisputed heavyweight champion of the world since Lennox Lewis.
And that's the fight he is screaming out for next."
#joshuaparker wasn’t the scrap I’d hoped it would be but AJ fought well & smart. Kept JP at end of jab. Ref seemed too hurried to break them up at times... but it was a clear win for AJ and he showed maturity & patience.#DAZN#DAZNGuestJudge#joshuaparker#Sponsored
"For how long will Anthony Joshua be allowed to enjoy this gritty, gruelling victory? Joseph Parker, a previously undefeated world champion, became the first man to take him the distance and briefly threatened to drag him into deep water, but it took mere minutes for his efforts to be forgotten and talk to switch to the one remaining heavyweight king: Deontay Wilder.
...
Parker's ability had been severely underestimated in the build-up to this fight. But although he demonstrated a capacity to weather Joshua's biggest shots — something no man previously has exhibited — he started the fight too slowly and failed to force the question: much as Hughie Fury did in Parker's previous fight."
Joseph Parker and Anthony Joshua touch gloves after the fight. Photo / Dean Purcell
"In just the second heavyweight unification bout between unbeaten champions in boxing history, Anthony Joshua cruised to a unanimous decision victory in a fight that produced more questions than answers about his ability.
Joshua, the WBA and IBF champion, went the distance for the first time in his career but failed to impress in a boring 12-round effort against WBO champion Joseph Parker in front of nearly 80,000 fans at Principality Stadium in Cardiff, Wales.
The fight was largely void of action, save for an exciting sixth round in which they traded power shots along the ropes. But even that sequence was instantly snuffed out by referee Giuseppe Quartarone, who continually robbed the fight of any excitement by constantly breaking them apart."
"Joshua (21-0, 20 KOs) added Parker's WBO belt to his IBF and WBA titles, maintaining his status as the world heavyweight No 1 and fulfilling what most expected would happen in front of 78,000 at the Principality Stadium in Cardiff, Wales.
But most also thought he would win by knockout, like he had his previous 20 professional fights.
Parker's movement foiled Joshua in his pursuit of a knockout, but the New Zealander did not land enough to win the rounds."
Good to see @joeboxerparker show so much class in defeat. You can tell a lot more about people by how they act in their difficult moments than their great ones. #JoshuaParker#boxing
"Joshua, almost a stone lighter than when he beat Carlos Takam in Cardiff last October, did enough without setting the fight alight, while Parker had his moments, even if an upset victory never looked on.
Joshua appeared relaxed as he walked to the ring in front of a sell-out crowd approaching 80,000, while Parker also lapped up the occasion during his entrance before both fighters got down to business and protected unbeaten records.
...
Parker's punches continued to fall well short as Joshua's jab proved effective for the British boxer to win a second round and continue leaving his opponent with no sign of finding his way into the contest."
"Anthony Joshua, taken the distance for the first time in 21 paid bouts, collected a third world title belt when he cruised to a convincing if drama-free win over the WBO champion, Joseph Parker, and looks in good shape to raise his game for what will be a more demanding assignment against Deontay Wilder.
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The British fighter, buoyed by the support of 80,000 fans in his third consecutive stadium fight (it was Parker's first), stalked his man methodically, wary of a countering right that has kept the New Zealander unbeaten. He is heavy-handed and busy rather than devastating, but Joshua was taking no risks.
The Joshua jab dictated the pace and intensity of the fight, and blood seeped from Parker's bottom lip. A short uppercut stunned him in a clinch in round three, the first inkling of vulnerability. Parker had never experienced such quality pressure in 24 fights and Joshua sensed it as he widened his lead."
Just shows to beat AJ you need a KO on sky sports. @joeboxerparker put a good close fight up. Just my opinion.
Anthony Joshua wins unanimously on points. Proud effort by Joseph Parker. Lasted 12 rounds. Two fine champions cancelling each other out. Fair result, no qualms. Shot Joe. #JoshuaParker
Well the god awful referee was only matched by the horrible scorecards. 118-110, 118-110, 119-109 in favour of Joshua. Are you kidding me? It was not that one sided at all. #JoshuaParker
