Tom Dillmann took his first Formula V8 3.5 victory by mastering a soaked Hungaroring and successfully fending off Roy Nissany by less than a second
The race also marked a first victory for Adrian Valles' AVF team, which entered the series during the later years of its Formula Renault 3.5 era.
"When you have taken four poles, I think it is about time to get a win," said Dillmann.
"I made a mistake on the first lap today and then lost another position to Aurelien [Panis] during the stops, so I was really getting hungry.
"When I returned to the track, I pushed really hard, but at the end Roy was quicker, so from the beginning to the end it was a tough race."
Hungarian-raised Israeli Nissany had an eventful afternoon, spinning from second to seventh at the final corner as the field went green for the first time, from its safety car start, on lap five.
He then set fastest lap as he sliced his way up the order, and executed a fine passing move on Panis for second exiting the Turn 7 chicane on lap 13.
"It was quite a strange race," said Nissany. "I felt more grip as the race progressed, but I think I reached Tom too late, and he is a really good defender.
"Anyway, I am happy to be here. At the restart early on I just had aquaplaning and spun off after getting too close to Tom."
Aragon winner Panis lacked the pace of several of his competitors, but the Arden racer shrugged off a grass-track moment avoiding the spinning Louis Deletraz on the exit of Turn 2 during a manic opening lap to claim a distant third.
Last year's FR3.5 runner-up Matthieu Vaxiviere was unfortunate to finish fifth after being wrong-footed by the timing of a safety car period, and losing further ground through a slow tyre change.
Vaxiviere had led at the completion of the first racing lap, having taken advantage when Dillmann suffered an aquaplaning moment.
But those runners to make their mandatory pit stops at the first opportunity on lap six, Dillmann, Nissany, Aurelien Panis, Louis Deletraz and Matevos Isaakyan, were handed a sizeable advantage by the deployment of the safety car on the following tour.
The race was neutralised while the damaged RP Motorsport car of Vitor Baptista was removed from a dangerous position at Turn 12.
Vaxiviere, Saturday winner Johnny Cecotto Jr, Pietro Fittipaldi, Egor Orudzhev and Rene Binder were the five drivers to have their races seriously compromised by failing to stop earlier.
Vaxiviere would battle back to fifth, thanks to a penultimate corner spin by Yu Kanamaru who had been engaged in a fierce fight for fourth with Deletraz over the closing laps.
Kanamaru had earlier grazed the barriers at high speed after bouncing wildly across the gravel trap at Turn 10.
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