ANTHONY JOSHUA WENT the 12-round distance for the first time as a professional in Cardiff tonight, but enjoyed a resounding if not wholly comfortable victory over previously undefeated Kiwi Joseph Parker.

The 28-year-old Briton adds the WBO World heavyweight title belt to his WBA and IBF straps, and in doing so moves a step closer to becoming the first undisputed World heavyweight champion since compatriot Lennox Lewis.

Joshua undoubtedly deserved his victory in a lukewarm fight often spoiled by infuriatingly fussy refereeing.

A tentative opening round, as both men sussed the other out, was difficult to score: Parker flicked out his jab to beat the band, but constantly short of its intended target – more a warning-slash-range-finder than anything. Joshua offered little by way of attack, but two solid right hands to Parker’s pelvis were probably more effective than anything thrown by the Kiwi during the first three minutes.

Parker was more forthcoming with his own right in the second, but one over-the-top miss was punished with a three-pronged assault on behalf of the Watford heavyweight – although Parker did find a home for an overhand right thrown seconds later.

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The Kiwi was conspicuously the faster fighter, but found himself perpetually in retreat early; Joshua, seemingly the better judge of distance – and far more nimble in his own right than he was versus Carlos Takam last time out – began committing more to fleeting combos throughout the third.

Parker swallowed a solid Joshua jab to begin the fourth and seemed briefly troubled, but the rest of the round was a non-event apart from a cuffing left hook by the Englishman which briefly checked Parker’s balance.

Parker returned serve with a fine jab of his own to open the fifth, and then – for the first time properly – lunged forward, landing three looping hooks on the backtracking Joshua’s solar plexus.

His jab again found its mark seconds later, but only as a precursor for the stinging right hand to the kisser which followed; the New Zealander’s best shot of the bout to that point rubber-stamped what was also his finest round.

Parker took his newfound momentum into the sixth, and enjoyed the better of a pulsating early exchange as referee Giuseppe Quartarone somewhat inexplicably tried – and largely failed – to intervene. A Joshua right hand skated over Parker’s shoulder and provoked a picture-perfect right uppercut counter; Parker, smirking, had come alive, and at the turn of the fight couldn’t have been more than two rounds behind.

When the Italian official – by this stage a pain in the arse – again attempted to split them in the seventh, Joshua unleashed a cheeky right uppercut of his own, not unlike the one which almost decapitated Wladimir Klitschko at Wembley last April. It missed narrowly, and while Parker’s trainer Kevin Barry went ape in his corner, Parker himself laughed it off with a touch of gloves.

Giuseppe Quartarone became too involved in the action in Cardiff PA Wire / PA Images PA Wire / PA Images / PA Images

The WBA and IBF champion came back to life in the eighth when he detonated a neat combination on his stopped WBO counterpart, doing enough to take the round in the process, and the ninth briefly reverted to the form of an earlier round: Joshua retook centre-ring, marching Parker clockwise with his jab, before Parker unleashed a three-punch combination – every component of which was blocked neatly by the home fighter.

Parker found some success to the body with a minute remaining in the 10th, but Joshua’s trademark right uppercut offered him a timely reminder as to why he’d opted against sticking in the pocket for the nine preceding rounds.

And so we went to the 11th – Joshua for just the second time in his career whereas Parker’s last three bouts had gone the 12-round distance. Again, it passed for the most part incident-free, though both fighters did exchange left hooks towards its finish: Parker was wobbled first but responded in kind, unsteadying Joshua ever so slightly with his gutsy riposte.

Parker continued to try the body in the final round but it struck as more a token gesture than anything; Joshua, doubtless up on the cards, seemed content to see it out to the bell.

That ding was met with mild boos by an underwhelmed 80,000-strong crowd who had the misfortune of watching Joshua go the full 12 rounds for the first time – this in his 21st professional contest.

The boos faded quickly, though, and the grinning Joshua once more received a hero’s acclaim as he awarded a unanimous decision on scores of 118-110, 118-110 and 119-109, adding the WBO bauble to his WBA and IBF equivalents.

Joshua called for a fight with Deontay Wilder in the aftermath, vowing to knock the Alabama’s WBC World heavyweight champion ‘spark out’ while flat-out refusing to fight in America.

Earlier on the card, Ireland’s Ryan Burnett successfully defended his WBA World bantamweight title.