The Roosters enter Sunday's grand final as clear favourites, but former Newcastle player Matty Johns sees Kalyn Ponga as the key to a Knights upset.
Johns has called Ponga the "best player in the world" and believes the fullback will need to deliver if Newcastle are to win the Provan-Summons trophy.
The Knights, last year's wooden spooners, are now 80 minutes from the title after beating Penrith, though the effort may have taken a heavy toll.
Johns has backed Newcastle as a genuine premiership threat throughout the finals, even when few agreed. He and former Roosters premiership-winner Cooper Cronk discussed the decider on 'Matty and Cronk'.
Cronk said the Roosters must "find a way to shut down" Ponga, adding that he would currently choose the Knights fullback over James Tedesco.
"It's crazy to say of Tedesco, a two-time Dally M medallist and two-time grand final winner who has captained his state," Cronk said.