Racing Engineering's Alexander Rossi took his third win from the last four GP2 races, surviving a carnage-filled feature race at Sochi.
The American kept his slim championship hopes alive by winning a race that featured two massive opening-lap crashes, a lengthy red flag stoppage and a surprising accident for then-leader Alex Lynn.
Before the carnage unfolded, it was Lynn who held the lead off the line, with Stoffel Vandoorne getting off to a slow start and dropping down to fifth.
Arthur Pic was among those who passed the Belgian and tried to dive around both Rossi and Pierre Gasly for second into T2, but ran slightly wide and slowed on the apex, allowing Rossi through.
He wasn't the only one running wide in the first corner, with numerous cars electing to take the runoff and then looking to rejoin the track at a high speed.
Among them was Artem Markelov, who hit the wall when trying to rejoin at way too high a speed and cutting across the white line.
The Russian went across the track, collecting Marlon Stockinger and Sergio Canamasas as the trio went straight off and into the wall.
Just a few hundred metres later, Jordan King joined them in retirement, having damaged his front wing earlier against a Status car and going straight on, his car burrowing deep into the Tecpro barrier.
A subsequent safety car turned into a red flag on lap 2 and the stoppage lasted for 30 minutes before the race – now shortened to 15 laps from the original distance of 28 – restarted.
Back under green flags, Lynn immediately pulled well clear of Rossi, who had to work on keeping Pic at bay - with Vandoorne looking to pass Gasly for fourth place.
On lap six, Lynn came in for the mandatory stop, rejoining in 17th place, with teammate Gasly opting to pit the next time around and Rossi following suit on lap eight.
The American then came out narrowly ahead of Lynn, but the Briton eased past the Manor F1 driver on warmer tyres.
Vandoorne, however, opted to stay out, soon clearing Pic when the Campos driver locked up under braking and ran wide.
But while Pic avoided further drama, Lynn didn't, crashing out of the provisional lead when he ran wide at Turn 13 and hitting the wall with his front left tyre. He had previously overshot Turn 2, and appeared to be struggling either with his tyres or brakes.
His retirement meant that the ongoing fight between Rossi and Gasly was for the win – and the American held off the Frenchman to secure the top spot.
Vandoorne completed the podium and picked up the fastest lap of the race on his final attempt.
Local driver Sergey Sirotkin fought his way up to fourth, ahead of Rio Haryanto, Raffaele Marciello, Stanaway and Pic, who will start from reverse-grid pole tomorrow.
Newcomer Dean Stoneman finished ninth, scoring two points on his GP2 debut, while Nobuharu Matsushita picked up tenth place after a five-second penalty for track limits for Mitch Evans.