Boxing: Former All Blacks, NRL star Sonny Bill Williams stuns Aussie rules legend Barry Hall with first-round knockout

All Blacks and NRL legend Sonny Bill Williams has added a somewhat dubious chapter to his incredible sporting legacy, comprehensively dispatching former Aussie rules star Barry Hall in the first round of their boxing showdown at Sydney.

In what was loosely described as a professional bout, the former NZ heavyweight champion needed less than two minutes to silence his trash-talking rival, 10 years his senior, as two supreme athletes provided a stunning anti-climax to their much-hyped encounter.

While Williams, 35, had some pro pedigree to call on, unbeaten now after nine fights, Hall's only previous venture into the ring was a controversial draw against rugby league hardman Paul Gallen, a result both still claim as a victory.

The Kiwi prepared for this bout with world heavyweight supremo Tyson Fury and former world champion Joseph Parker, under trainer Andy Lee in England, an environment guaranteed to have him in top condition.

While many expected Hall to take the fight to Williams, their few seconds of combat unfolded in exactly the opposite manner, with SBW on the front foot and pressing forward, immediately having his rival, 10k lighter, in trouble.

After just 48 seconds, Hall caught a right to the side of the head and crumbled to the canvas, but his fall could easily have been a slip and the ref was unsighted. No such confusion with his subsequent trips to the floor.

At 1m 34 seconds, Williams hit Hall in the head with a swinging right and followed with a straight left to the chin, sending the Aussie to his knees once more.

Counted back into the fight, Hall walked into a straight left from Williams, and collapsed against the ropes for the third and final time.

The result sent social media into overdrive, with many claiming the contest a farce and not worth the $50 pay-per-view cost asked by new streaming platform Stan Event.

What's next for Williams?

"Well, there's talk of Gallen, so maybe Gallen," he offers.

The former Cronulla Sharks captain was ringside for the fight and was spotted already in Williams' ear, as he left the arena.

While that proposition might delight league fans, boxing aficionados might think twice before investing in another such crosscode extravaganza.

A much more palatable spectacle for the purists was the 10-round co-main event between super-featherweights Paul Fleming and Jackson England, who threw more than 500 punches each in a bout that could have gone either way, but eventually went to Fleming by unanimous points, despite his visit to the canvas in the second round.