Joseph Parker has surrendered his WBO heavyweight world title following a 12-round fight with unbeaten Brit Anthony Joshua at Cardiff's Principality Stadium.

The 26-year-old Aucklander became the first man to stretch Joshua, who moves to 21-0, the full 12 rounds but was defeated by unanimous decision on Saturday.

The Watford-born 28-year-old now holds the IBF, IBO, WBO and WBA belts. Two of the three judges scored it 118-110 in Joshua's favour with the third giving it to the London Olympic champion 119-109.

Parker, who earned 7 million for his trouble, told Sky Sports after the fight he had no regrets.

"I lost to the better champion tonight," he said. "It's a good experience to be here. We'll be back. I'm young, I'm strong."

Joshua paid tribute to Parker in the ring.

"Forget the hype, Joseph Parker is a world champion. I knew he'd be determined," he said.

"Sometimes this does become a boxing match, not a fight, so I made sure this would be about boxing finesse."

With an ultimate unification bout against WBC champion Deontay Wilder - and the chance to become the first undisputed world champion since 2000 - on the line, a composed Joshua was mostly dominant.

There were few clean punches in a tense opening stanza as both boxers felt each other out, an energetic Parker however unable to stop Joshua dominating the middle of the ring.

A cut above Parker's left eye was evident from the third round on as he was again forced to expend energy trying to move a steadfast Joshua around.

He managed a few good punches in the fifth before unleashing a torrent following a Joshua uppercut not dissimilar to the one which ended Wladimir Klitschko's career at Wembley Stadium last year.

It was a different Parker throughout the middle rounds but by the time the cut above his eye worsened in the 10th both the raucous crowd and Joshua could smell blood.

A crowd of almost 80,000 was on hand at Wales' national stadium with American legend Sugar Ray Leonard and former Chelsea and Netherlands striker Jimmy Floyd Hasselbaink among those ringside.

Joshua took more than 10 minutes to enter the ring, standing on a platform amid fireworks and flamethrowers in scenes reminiscent of the WWE.

His opponent was perhaps given some extra motivation when sections of the crowd booed the Samoan and New Zealand national anthems.

There was controversy before the bout when Parker had his hand wraps questioned.

The Kiwi's promoter, David Higgins of Duco Events, told media during the penultimate undercard fight that the wraps were queried by an official at the behest of Joshua's camp.

British Boxing Board of Control head Robert Smith, however, sided with Team Parker and the wraps remained unchanged.