Anthony Joshua has set his sights on a heavyweight showdown with American Deontay Wilder after claiming a unanimous points victory over Joseph Parker in Cardiff.

Promoter Eddie Hearn believes the Wilder fight "has to happen in 2018," and if it does, a win for British star Joshua would add the WBC title to his collection and make him an undisputed world heavyweight champion.

Watford's world champion said: "2018 was always a time to capture all the belts. We are one away now.

"It has been a big question that was asked after the fight. I am not into the business of hype, hype, talk, talk.

"I would love to maybe go to America with Eddie and Rob (Joshua's trainer Rob McCracken) and look at the landscape and deal with this behind closed doors.

"But a lot of negotiations can go on over social media and YouTube and stuff, but when you are doing serious business, you have to sit down in confidential privacy and then we can see how serious people are about taking the fight."

Hearn, meanwhile, added: "I think it (Wilder fight) has to happen in 2018 otherwise we are going to hit some major problems with the politics and the mandatories.

"If they (Wilder's management) stepped up and were actually serious about the fight, and serious about a deal we are more than fair to offer them, it could happen next.

"But they are so erratic and unpredictable, I don't know what to believe."

The former Finchley ABC boxer won the first heavyweight unification bout held on British soil as he saw off New Zealander Parker in front of a crowd approaching 80,000 at the Principality Stadium.

Joshua added the WBO belt to the WBA and IBF belts he already holds, but he was taken the distance for the first time in his professional career.

It was his 21st straight career victory, although previously unbeaten Parker delivered a battling display without seriously troubling Joshua.

Two judges awarded the fight to Joshua 118-110, with another scoring it 119-109, although regular interventions by Italian referee Giuseppe Quartarone did not help the fight develop any free-flowing nature.

Joshua said: "I am not elated because I don't let the highs get to my head. And I always think we've got to go again soon.

"If I was retiring on this high, I would be like, 'yes, I'm the man'.

"But I have to defend my throne again in a few months. I am balanced. We are still hustling, We are on to the next one, and in my eyes, it's not time to sit back and enjoy the ride."

Reflecting on his loss, Parker said: "We enjoyed being here. He deserved to win, and we are disappointed, but we will be back.

"He (Joshua) is a good fighter, and today he showed he could box."

Asked about the referee's performance, Parker's trainer Kevin Barry said: "Obviously, when one guy (Parker) has got a 76-inch reach and the other guy has got 84 or 85 (Joshua), it's important when we do close the distance that we are able to work.

"Unfortunately for us, the referee just didn't allow us to do that.

"I thought today we were beaten by a better man. I was quite impressed with a lot of things Joshua did. He held his hands better and was quite hard to hit."