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The Knights came out firing in the second half after trailing by a converted try at the break. (Getty Images: Corey Davis)

A blinding second-half performance from the Knights led to a 25-20 victory over South Sydney in Newcastle this evening, leaving the Rabbitohs without a win in five starts.

Trailing 12-6 at the break, the Knights piled on three tries after the restart with Jarrod Mullen crafting two of them and coolly adding a field goal in the 74th minute.

His chipped one-pointer made the score at that stage 25-12, giving the Knights enough breathing space for the win despite late tries to Chris Sandow and Jamie Simpson.

Mullen told Fox Sports that some choice words from coach Brian Smith during the half-time break gave the Knights players the wake-up call they needed.

"He gave us a bit of a blasting, we lost a lot of ball down our end and especially against a side like Souths who like to throw the ball around you can't do that," he said.

"He gave us a bit of a rev up and we came out in the second half firing. We played a lot smarter and a lot tougher (after half-time).

"We ended up getting the points in the end, but it was a little disappointing they came back there... we need a lot of that desperation defence but it was a good win all up."

Jarrod Mullen grappled with South Sydney playmaker John Sutton. (Getty Images: Corey Davis)

Mullen and Isaac De Gois gave Newcastle a lethal one-two punch on the attack, with Mullen's confident long passing wreaking havoc on South Sydney's edge defence.

Some selective kicking in the Knights' attacking 20m kept the Rabbitohs' guessing and another cool-headed performance from Mullen will certainly make him a chance to play for NSW in Origin III.

De Gois was similarly threatening around the ruck, and picked up a try assist when he turned the ball back inside for Richard Fa'aoso to score six minutes into the second stanza.

Senior Knights forward Steve Simpson said it was nice to crown his milestone 200th appearance with a win.

"It was great to celebrate it at home in front of a packed house and a good crowd for a Monday night," he said.

"The first half was a little bit scratchy... but the boys really pulled together really tight there in the second half and we came home with it well which was great."

Newcastle: 25 (A Uate, R Fa'aoso, K Lulia, S Simpson tries; K Gidley 3/4 conversions, penalty goal; J Mullen field goal)

South Sydney: 20 (J Simpson 2, M Crocker, D Faalogo tries; I Luke 2/4 conversions)