The Knights lost five-eighth Anthony Milford to the sin-bin less than a minute before halftime, along with Dom Young at the break and Tyson Frizell shortly after to injuries, and while they scored first in the second half to trail 14-12 they couldn't contain a rampant Manly.

The Sea Eagles scored five tries in the second half, powering through the visitors, to claim a comprehensive victory in front of 15,896 fans.

Newcastle's loss, their 12th this season, leaves them facing a near impossible task to make the finals.

With seven games left to play, they now sit eight points outside the top eight.

They would need to win likely all their remaining games and hope results go their way to have any chance of making the finals for a third consecutive year.

Knights coach Adam O'Brien had admitted it was basically make or break in terms of the finals before the game, but his side were completely overrun by the home team in the second stanza.

O'Brien wouldn't concede the Knights were out of the running after the game.

"I don't know, I don't have a calculator," he said.

"I just focus on the Roosters now.

"We'll have a look at what we need to get better at from tonight and take it one week at a time."

The Knights had started the game well and almost scored after only a couple of minutes but winger Edrick Lee got held up over the try-line.

Manly posted the first points when centre Tolutau Koula embarrassed Enari Tuala with a skip and step to cross on the right edge after 11 minutes.

The play came after Newcastle blew quality field position with an error and then gave away an escort penalty on the last tackle.

The Knights hit back a few minutes later after Dominic Young made a break down the right flank and kicked infield for halfback Adam Clune.

They would hold a 6-4 lead for almost 20 minutes until Manly made a break down the left edge and winger Jason Saab scored his side's second.

Newcastle's right-side defence had been caught out badly near halfway with Manly back-rower Andrew Davey simply having to attract Kalyn Ponga at the back and pass to Saab to ice the play.

Milford, playing his 200^th game, got sin-binned for holding Manly fullback Reuben Garrick back as the Sea Eagles were made a similar break a few minutes later.

It allowed the home side to take a 14-6 lead into halftime following a penalty kick and play with a man advantage for the opening 10 minutes of the second half.

Four minutes after the break, with his side trailing 14-6 and Milford still in the bin, Knights skipper Kalyn Ponga put Lachlan Fitzgibbon in a gap near halfway and then backed up to run onto a pass from Enari Tuala further downfield before scoring to the left of the goalposts.

The try helped reduced the deficit to only two points but Manly extended their lead as Miflord returned to the field when Jason Saab scored his second in the 49th minute.

Haumole Olakau'atu, Andrew Davey, Christian Tuipulotu and Lachlan Croker scored in the final half hour.

Newcastle had limited possession much of the second half and were unable to create any real opportunities.

They lost winger Dom Young to a rib injury at halftime and his replacement Simi Sasagi left the field clutching his left arm late in the game. Tyson Frizell also failed to play out the game.

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