The Knights overcame the loss of Test forwards Tyson Frizell and Kai Pearce-Paul to keep their finals hopes alive with a 36-16 defeat of South Sydney.
Rabbitohs captain Cameron Murray was sent to the sinbin just before halftime after a high shot on Frizell, who was deemed to have shown Category 1 HIA symptoms and ruled out of the match.
Pearce-Paul had come from the field just minutes earlier and the English second-rower was taken to hospital after suffering a severe laceration to his leg.
Newcastle led 18-12 when they lost the star second-rowers and they went on with the job to join the Broncos, Dolphins and Raiders on 26 points - just two behind the eighth placed Dragons.
The Knights play the Titans next weekend, while the Dolphins face the Broncos and the Raiders take on the Roosters.
Newcastle host the Dolphins in their final regular season match on September 8, while the Broncos play the Storm and the Raiders face the Dragons.
The Knights took an early lead when fullback Kalyn Ponga combined with centre Dane Gagai to send winger David Sharpe racing for the corner in the 12th minute.
However, Souths hit back after star playmaker Jack Wighton created a try for centre Taane Milne in the 17th minute and scored one himself just three minutes later to put the home side ahead 12-6.
Taane Milne Try
Wighton tried to inspire his side with a heavy shot on former NSW Origin team-mate Tyson Frizell but the Knights regained momentum when Dylan Lucas beat four defenders to score in the 33rd minute.
Gagai then put the Knights ahead before halftime when he stepped his way over to score and things went from bad to worse for Souths after Cameron Murray was sinbinned.
Dane Gagai Try
The Rabbitohs captain was given his marching orders after making high contact with Frizell, who was ruled out of the match after being deemed a Category 1 HIA.
A Ponga penalty goal gave the Knights a 20-12 lead at the interval and they went on with it in the second half to keep their finals hopes alive.
Five-eighth Jack Cogger started and finished Newcastle's first try after the interval when he put Ponga into space and backed up the sidestepping fullback to score in the 53rd minute.
Cogger then scored his second try five minutes later after slicing through the South Sydney defence near the line to put the Knights ahead 32-12.
Jack Cogger 2nd Try
Rabbitohs forward Tallis Duncan scored his side's only second half try in the 70th minute but any thoughts of a late comeback were snuffed out when Gagai crossed again.
Match: Rabbitohs v Knights
Round 25 -
home Team
Rabbitohs
15th Position
away Team
Knights
11th Position
Venue: Accor Stadium, Sydney
Match snapshot
Ponga goose steps into open space
- Rabbitohs captain Cameron Murray was sent to the sin bin for a high shot that forced his former NSW backrow partner Tyson Frizell out of the game.
- Sebastian Su'a made his NRL debut after the Knights activated him as their 18th man following the loss of Tyson Frizell due to foul play.
- Su'a's night finished early, with the 20-year-old sinbinned and placed on report after his shoulder connected with the head of Davvy Moale while attempting a tackle.
- Newcastle centre Dane Gagai played against his brother Jacob for the first time and scored two tries, while making eight tackle breaks.
- Knights captain Kalyn Ponga ran 144 metres with the ball, producing two line breaks, a try assists and six tackle breaks.
Play of the game
Jack Cogger 1st Try
What they said
Rabbitohs: Round 25
Knights: Round 25