Handicapped by injury and concussions, Newcastle produced a desperate defensive display to deny the Sea Eagles, who spent most of the second half on the attack.

There were dramatic scenes on full-time when Manly forward Addin Fonua-Blake was sent off for dissent.

Newcastle's gritty, gutsy display was the perfect response to last week's lacklustre 32-20 loss to North Queensland.

It lifted them above the Roosters to fourth on the ladder and sets up a blockbuster next Sunday with competition leaders Parramatta at McDonald Jones Stadium.

The Knights led 14-6 at half-time but suffered two significant body blows.

Winger Edrick Lee was forced off in the sixth minute, clutching his left forearm, which he broke last year.

He was later photographed with his arm heavily bandaged.

Then in the 39^th minute, back-rower Sione Mata'utia, who suffered a series of concussions earlier in his career, was left dazed after attempting a tackle on Manly's Cade Cust.

Mata'utia failed his head-injury assessment and was unable to return.

That meant Newcastle were down to 15 men for the second half.

The Knights opened the scoring with a Kalyn Ponga penalty goal in the seventh minute, when Manly skipper Daly Cherry-Evans was sin-binned for impeding Lachlan Fitzgibbon as he chased a Mitchell Pearce grubber kick.

Newcastle made the most of their numerical advantage and early possession when hooker Andrew McCullough scored from dummy-half in the 14^th minute.

Cherry-Evans wasted no time in making amends, darting through the middle of the ruck to score in the 21^st minute and reduce the deficit to 8-6.

The Knights received a massive boost on the stroke of half-time when Pearce chip-kicked and five-eighth Kurt Mann juggled to score.

Adding to Newcastle's injury woes, lock Herman Ese'ese was struggling early in the second half with a knee injury that required strapping.

Manly thought they had scored in the 60^th minute after Ponga dropped a bomb, but the video referee ruled centre Brad Parker knocked the ball forward before Ponga's fumble.

The Knights eventually succumbed to sustained Manly pressure and Cust scored in the 66^th minute, leaving the visitors clinging to a 14-12 lead.

Two minutes later, Ponga dropped another bomb but the video referee denied Cherry-Evans a try because of a Danny Levi knock-on.

Ponga, however, was taken from the field for a head-injury assessment.

Sea Eagles winger Tevit Funa broke clear in the dying seconds and, after kicking ahead, appeared to receive a push in the back, prompting Manly players to remonstrate with referee Grant Atkins, who gave Fonua-Blake his marching orders.