The MP Motorsport driver lined up second before taking the lead at Turn 1 from polesitter Kush Maini (Campos).
He managed to build a solid lead over second-placed Iwasa (DAMS) and although the Japanese driver began to close after a virtual safety car, he cleared off into the distance finish 4.2s clear.
Iwasa had lined up fifth and made a fantastic start, jumping up to second by Turn 2 before setting about chasing Hauger.
For five laps in the closing stages he put in faster laps than the Norwegian, but eventually proved unable to launch a move and settled for second.
Oliver Bearman snatched third from Theo Pourchaire for his fourth podium of the season, catching the ART title contender sleeping at Turn 1 to help Prema team-mate Frederik Vesti cling onto his championship lead.
At the start, Hauger took the lead from Maini into Turn 1 as the Indian driver locked up, with Iwasa swooping into second around the outside of Turn 2.
Bearman, meanwhile, had a strong start from fourth and also cleared Maini to run third by lap two, only for the poleman to take back third the following lap at Turn 1, braking late to pass his fellow rookie as Pourchaire closed on the pair.
Hauger was 1.7s clear of Iwasa by lap four, a gap which shrunk to 1.3s by lap 12 when the VSC was deployed after contact between Clement Novalak (Trident) and Campos driver Ralph Boschung.
Novalak attempted a move up the inside of Turn 1 but made contact with the Swiss, with Boschung running into the barriers, while Arthur Leclerc (DAMS) was also caught up in the tangle but continued.
Racing resumed on lap 13, with Pourchaire getting the jump on Bearman to snatch fourth up the inside of Turn 2.
Hauger was 2.5s clear on lap 18 when Iwasa was told he could push and put in strong lap times to slash the gap to just one second by lap 24 before falling back again.
Pourchaire passed Maini at Turn 1 to take third with brief contact from behind from the Campos driver, though both escaped unscathed. Bearman then squeezed through at Turn 2 for fourth, demoting Maini two positions in as many corners.
Bearman then made it past Pourchaire with two laps remaining to steal the final podium spot.
Jehan Daruvala, who lined up third for MP Motorsport but struggled with his start, finished fifth, having passed Maini at Turn 2 on the final lap.
Victor Martins finished seventh for ART, with Isack Hadjar rounding off the points-paying positions for Hitech.
Though Vesti missed out on the points in ninth, Bearman passing Pourchaire salvaged his lead which stands at one point heading into Sunday’s race.
