Holbrook has taken last year's wooden spooners and sprinkled his magic dust into each and every player at the Knights to win through to Sunday's decider against the Sydney Roosters.
In the 19-man squad named for the grand final, only halfback Sandon Smith, hooker Harrison Graham and bench forward Pasami Saulo were not at the club in some capacity in 2025.
It was the same story at Gungahlin, in Canberra's north, 18 years ago when former NRL prop Mark Nicholls played under Holbrook as an 18-year-old in the Canberra Raiders Cup competition.
"I spoke to (Knights centre) Dane Gagai when I was at Jai Arrow's 100th game for Souths and he mentioned that Justin had been the perfect coach this year for where the team was at," Nicholls told AAP.
"Justin was doing essentially the same thing as a coach 18 years ago at the Bulls that he is doing now at the Knights.
"Back in 2008 we had a lot of talent in the team but we hadn't been able to put it together for a few years. Justin came in as coach and with a very similar side he got us disciplined, playing to our strengths and into a grand final."
Nicholls played 194 NRL games and was known affectionately as "the GOAT", not because he was the greatest of all time but due to the way he made the greatest use of his talents to become an outstanding prop.
Holbrook will truly become "the GOAT" of coaches if he can win with Newcastle on grand final day.
A victory would secure history for Holbrook and the Knights - who finished seventh in the home and away season - as the first side to win a title from outside the top four in the NRL era.
At Gungahlin Bulls, Holbrook inherited a team that had finished sixth to miss the finals in 2007, but had future NRL players Nicholls, Paul Vaughan and Tim Weyman on deck.
"One thing I remember clearly about Justin was that he had this confident and calm demeanour about him as a coach," Nicholls said.
"As a young fella I certainly picked up on it and it rubbed off on all of us.
"He brought a talented team together and made us all better"
Gungahlin suffered a late-season injury crisis and lost that 2008 grand final to Queanbeyan Blues with Nicholls having to play in the centres.
Holbrook, who had arrived at the Bulls after captain-coaching Dapto Canaries to the 2006 title in a five-year stint, went from his one season at Gungahlin to Canterbury - leaving his soft drink career behind - and his career as a coach kicked off.
Nicholls' career took a different path to that of Holbrook but he said the Knights mentor reminded him of his old Dolphins coach Kristian Woolf who had gone via Townsville Blackhawks and Super League to the NRL.
"Some coaches have great playing careers and go into NRL assistant roles and coach years later," Nicholls said.
"Others do the hard yards and improve their craft like Justin as a coach and me as a player in country footy.
"They get better everywhere they go and figure out what works. By the time they get to the NRL they know who they are and what they stand for as a coach and are ready to go. That's exactly what Justin did."
