Anthony Seibold’s experimental spine has backfired with Brisbane imploding in their 26-12 NRL loss to Newcastle at McDonald Jones Stadium.

After they were pegged as pre-season top four contenders, the Broncos could be in the bottom four by the end of the weekend following their third straight loss.

Seibold rolled the dice on Saturday when he moved playmaker Anthony Milford to fullback in a positional swap with Darius Boyd, but the bold gambit failing to have its intended effect.

Boyd – playing his first first-grade game at five-eighth – was quiet all night, running for just seven metres before being steamrolled by Jesse Ramien which allowed Mason Lino to score the match-winner in the 69th minute.

Despite having 44 tackles inside the Knights’ 20-metre zone – compared to the Knights’ 11 – they were still out-scored four tries to two and never really looked in the contest.

The Knights were dealt a massive blow when star Kalyn Ponga was ruled out an hour before kick-off with a calf injury which is threatening to rule him out of State of Origin III.

While Ponga’s injury prompted a reshuffle, they lost little as Kurt Mann moved to fullback with the 26-year-old utility throwing the last pass for Edrick Lee’s and Lachlan Fitzgibbon’s tries as the home side burst out of the blocks.

Ponga insists he will be right for the Origin decider on Wednesday week while his potential replacement Lee was unfortunately ruled out of a possible Maroons’ debut after suffering a suspected broken arm.

Knights and NSW prop David Klemmer put in a typical five-star performance his return from a fractured wrist, playing the opening 49 minutes, running for 196 metres and making 26 tackles.

The Knights smelt blood in the water at 18-0 up at halftime but couldn’t have started the second-half in less impressive fashion.

Halfback Mitchell Pearce – who has been sized up for a NSW jumper – failed to make touch twice in the space of three minutes and prop James Gavet was dubiously sin-binned for a high shot on Andrew McCullough.

The Broncos made the most of the extra man via a Thomas Flegler fly.

And when Hymel Hunt spilled the ball seven metres from his own line, Kotoni Staggs crossed to make it an eight-point ball game.

But when Ramien ran through some feeble defence from Boyd, it killed off any threat of a Broncos fightback.