The opening exchanges followed suit, with both forward packs coming together in some heavy collisions, but the Junior Kangaroos gained the early ascendancy through their quick and efficient work around the ruck.
Despite the cold and wet spring conditions, it took barely five minutes for the visitors to open their account, with Cronulla Sharks winger and former Junior Kiwi, Valentine Holmes, powering over before Gutherson added the extras off the boot.
The Junior Kiwis responded on the 20-minute mark when a big overlap allowed West Tigers' centre Watson Heleta to score, but Parramatta halfback Zach Dockar-Clay's conversion attempt went wide.
The hosts were fortunate to add to their tally soon after, when a blatant forward pass gave Newcastle wing Chance Peni their second four-pointer, which together with the conversion provided a four-point buffer.
The Junior Kangaroos hit back just before the break when a penalty put them within range before numbers out to the left gave their own Knights' winger, Jake Mamo, a try to level things at 10-10.
The Junior Kangaroos lacked energy in the early stages of the second-half before Broncos prospect and Junior Kiwis fullback, Kodi Nikorima, beat a number of players on a jinking run to score their third, but Dockar-Clay's goal attempt was off-target.
In typical green and gold fashion, the Junior Kangaroos worked downfield for Holmes to claim his second of the night and once again level the scores to set up a tense and physical final quarter.
With fulltime looming, both sides attempted field goals but were unable to break the dead-lock, before a midfield break from Dockar-Clay helped set up a the winning shot from Martin.
"We don't have to practice things like that. These kids are professional footballers, they know it's a one-point situation and the message has gone out," Junior Kiwis coach Brent Gemmell said of his side's composure.
Despite the trying conditions, he was pleased with his side's ball security and execution under pressure.
"There's enough football talent on the field. We just strung those possession stats the right way," he said.
Junior Kiwis 15 (Heleta, Pene, Nikorima tries; Dockar-Clay goal; Martin field goal)
Junior Kangaroos 14 (Holmes 2, Mamo tries; Gutherson 1 goal)