Playing their fourth match in 15 days, the Jets maintained their hold of second spot on the ladder and edged closer to the club's first finals appearance since 2009-10.
It is Newcastle's 10th win of the campaign, equalling the team's record for most wins outside their grand-final season of a decade ago, and they have collected 16 of a possible 21 points since December 9.
There were several near-misses and saved opportunities on Friday night but Jets defender-turned-attacker Jason Hoffman provided the match winner in the 11th minute.
The 28-year-old netted his third of 2017-18 and extended Newcastle's goal-scoring streak to 16-straight games.
The left-footed strike was slotted past Roar goalkeeper Jamie Young.
The goal came courtesy of a transition from deep in the host's own territory, including long balls from Dimitri Petratos and Daniel Georgievski, before a deft flick inside from Andrew Nabbout along the 18-yard line.
Four yellow cards were issued, including Roar defender Avram Papadopoulos, who was returning from a seven-match suspension for spitting at an opponent in November.
In the 14th minute, the crowd of 12,137 stood and applauded as a mark of respect for Queensland schoolgirl Amy "Dolly" Everett, who took her own life on January 3 after being bullied online. She was 14.
Earlier at Newcastle, W-League title aspirants the Jets were upset 2-1 by last-placed Adelaide.
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