A incident-strewn feature race, which came after an abandoned sprint race on Saturday, saw four of the top six in the standings crash out, while the remaining two were handed 10-second penalties for collisions.
The mixed-up order saw Trident driver Novalak, who had scored just two points in 2023 before this weekend, take his first win since his title-winning BRDC F3 campaign in 2019.
Lining up 13th, Novalak was inside the top 10 by the first safety car, which came moments into the opening lap as Jack Doohan spun into retirement on the run to the banked Turn 14, while up ahead Frederik Vesti also rotated but kept his Prema-run car going.
Racing resumed on lap four, with pitstops commencing a few laps later as poleman Jak Crawford retained the lead for Hitech.
Championship leader Theo Pourchaire was next to crash out, heading straight into the Turn 7 barriers on his post-stop outlap.
Novalak and both Prema cars headed into the pits before the safety car was deployed but Vesti soon encountered trouble as both his rear tyres parted company with his car, putting the Dane out too.
The safety car period ended on lap 16 as Prema's Ollie Bearman and Victor Martins (ART) clashed, with with Briton retiring and his adversary handed a 10-second penalty.
But Novalak held firm and took his maiden win, with Zane Maloney in second for Rodin Carlin ahead of Crawford.
The only driver in the top five in the standings to score was Martins, demoted to ninth by his penalty as Iwasa, who also received a penalty, finished 13th.
Source: Autosport