Gritty Newcastle displayed defensive steel after losing key playmaker Jarrod Mullen and stayed on course for the NRL finals with a courageous 23-4 win over Canberra at EnergyAustralia Stadium on Saturday night.

The Knights spent much of the match defending and played all but the first five minutes without Mullen, who suffered ankle ligament damage.

Newcastle started the round in seventh spot, while Canberra have dropped to 11th below South Sydney, four points outside the eight.

Up 16-0 at the break, Newcastle tallied four tries to one and held Canberra scoreless for almost an hour.

The Raiders dominated territory in the first and third quarters but failed to capitalise on the vast majority of their possession.

A 56th minute Joel Monaghan try from a Marc Herbert bomb was the Canberra's only reward.

For 12 first-half minutes, the Knights were down to just 15 fit players while prop Mark Taufua was benched with a shoulder problem.

Taufua returned after 22 minutes and shortly after the Knights commenced their decisive second-quarter scoring surge.

Canberra contributed mightily to their own downfall as two of Newcastle's three tries came after the Raiders conceded penalties deep in their own half while the third emanated from a horrid error.

Veteran centre Adam MacDougall off-loaded the ball in a tackle to help set up the opening try to Richie Fa'aoso.

The Knights notched a second try five minutes later when winger Keith Lulia rounded off good lead-up work by hooker Isaac De Gois and skipper and second-rower Steve Simpson.

A fumble by centre Jarrod Croker 20 metres out from his own line inside the final two minutes of the half proved costly for Canberra.

From the ensuing scrum, winger Akuila Uate crashed over in the corner following a strong run by centre Junior Sau.

Canberra created a number of third-quarter opportunities but all were cruelled by poor handling and passing apart from Monaghan's well-timed jump.

Five-eighth Ben Rogers, who fed the scrums in Mullen's absence, effectively put the game beyond Canberra's reach with a 67th minute field goal to give Newcastle a 17-4 advantage.

Wes Naiqama, who came on for Mullen, added a 78th minute try and also nailed three shots at goal for a personal tally of 10 points.

Newcastle team doctor Peter McGeoch said Mullen's season would depend on a scan of the injury on Monday.

"It depends what grade it is, it could be as little as five weeks but the worse case scenario is the season," McGeoch said.

Mullen said the injury occurred when he tried to run the ball back on a last tackle.

"Which was probably a stupid option looking back on it now," he said.

"(Canberra captain) Alan Tongue tackled me and I think he must have heard it too, because he wanted to see if I was all right.

"I think the ankle just fell under his body, it was one of those freak accidents.

"My head was down after I came off the field, but to see the boys dig deep, that certainly puts a smile back on your face."

Newcastle coach Brian Smith lauded a heroic effort by his team, especially the Knights bench.

"We got 193 minutes off our bench tonight which would have to be a world record, it certainly is for us," Smith said.

"It just took every ounce of energy and effort and commitment from our players to defend in the second half like that, it was just amazing."

Canberra coach David Furner lamented his side's inability to prevent Newcastle's second-quarter scoring surge.

"We spoke about that 20-minute period before halftime when they score a lot of their points and did tonight," Furner said.

"I thought our line defence let us down a little bit. They had three opportunities on our line and they scored three tries."

Brought to you by AAP © 2024 AAP