A relentless South Sydney side have flexed their muscle by destroying a hapless Newcastle 52-6 at ANZ Stadium on Saturday night.

On the same day the Knights lost key playmaker Jarrod Mullen for the season, the Rabbitohs recorded their biggest ever victory over Newcastle, surpassing last year’s 40-point rout in Cairns.

The win consolidates the Rabbitohs’ spot in the top four, while Newcastle’s loss, their 12th in 14 games, all but ends their faint finals hopes.

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Skipper Greg Inglis and Alex Johnston both bagged hat-tricks, centre Dylan Walker recorded a double and hooker Issac Luke ran rampant behind a dominant Souths pack.

If it wasn’t for Adam Reynolds’ off-night with the boot – he nailed just six goals from 10 attempts – the Rabbitohs would have surpassed their biggest ever win at ANZ stadium.

An upset could have been on the cards when Knights prop Kade Snowden crashed over untouched in just the 2nd minute.

Greg Inglis was at his best for the Rabbitohs. Photo: Getty

But it took only three minutes for their dream start to turn into a nightmare, as Rabbitohs centre Walker finished off a 60-metre blindside play that also saw opposite three-quarter James McManus’s night end with concussion.

The early setback seemed to flick the switch for the defending premiers, with Johnston burning Chanel Mata’utia in the 10th, John Sutton offloading for Inglis in the 15th and then Bryson Goodwin going over on play one of a scrum win in the 23rd.

Co-owner Russell Crowe was watching on from the stands and the only opponent the Rabbitohs seemed to be playing was the clock.

The carnage continued when Inglis stretched out to nab his second try in the 27th.

Walker notched his brace in the 33rd, before Inglis celebrated his hat-trick in the 40th by bringing out his goanna celebration.

By the end of a first half, the Rabbitohs led 36-6.

The points somewhat dried in the second half, with Thomas Burgess crashing through in the 49th, Johnston soaring over Mata’utia in the 59th and then Walker completing his own hat-trick in the 73rd.

The NRL playoff hopes of the New Zealand Warriors have taken a hit with star half-back Shaun Johnson’s season-ending ankle injury.

Coach Andrew McFadden confirmed the seriousness of Johnson’s injury after his side’s 32-12 defeat to the Manly Sea Eagles in Auckland on Saturday.

Johnson had to be helped from the field by trainers. Photo: Getty

The playmaker limped off in the 25th minute after another typical piece of magic, skipping past three defenders to score his side’s opening try.

The 24-year-old Johnson, the Golden Boot winner last year as league’s best player, had shown some sublime form in recent weeks.

Both sides were locked level at 6-6 at the break but Manly ran in five tries in the second half, with Brett Stewart and Jorge Taufua scoring doubles.

And earlier, hometown hero Tohu Harris had a hand in two tries as the Melbourne Storm’s Napier experiment paid off in style, downing St George Illawarra 22-4 at McLean Park.

A crowd of 14,532 witnessed the first NRL match in the Hawke’s Bay city and were treated to a masterclass by the Storm at their efficient best to condemn the Dragons to their seventh straight loss.

The only negative for Craig Bellamy’s men was the sight of Cooper Cronk leaving the field late on with what appeared to be a quad injury.

Nelson Asofa-Solomona and Marika Koroibete crossed for first-half tries for the Storm, and Kevin Proctor and Mahe Fonua joined in the party after the break.

St George’s only score of the game came with two minutes left, when Peter Mata’utia posted a consolation try.