World champion Anthony Joshua won the first heavyweight unification bout held on British soil as he gained a unanimous points verdict against Joseph Parker at Cardiff's Principality Stadium.

The Watford star 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 New Zealander Parker delivered a battling display without seriously troubling Joshua.

Talk will now further intensify of Joshua fighting unbeaten American and current WBC heavyweight champion Deontay Wilder for all four belts.

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.

Both men tried to get their jabs going in the first round, and Joshua began to back Parker up in the closing stages of an opening three minutes that he shaded after dominating the centre of the ring.

Joshua's superior reach and jabbing prowess ensured that Parker remained on the back foot in round two, and there were also signs of the Kiwi having a bloodied nose.

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.

Parker began to cut something of a frustrated figure, and the fight's pattern seemed well set by the third round as Joshua continued to make the most of his reach advantage, although there was a concerning moment when the pair clashed heads before Joshua banked another round.

Round four followed a similar pattern, then Joshua caught his opponent with a couple of powerful body shots in round five before Parker tried to raise the tempo, and it proved his best spell of a fascinating encounter.

Parker had noticeably increased his work-rate, although Joshua still held control and he got a quickfire combination going at the end of round eight which ended a quiet spell for the British star.

A cut opened up near Parker's left eye in round 10, and although he produced his most effective punch of the contest in the next round, Joshua had already done more than enough.