Johnny Cecotto Jr scored his maiden GP2 Series victory in the Monaco feature race after keeping Marcus Ericsson behind in a race-long battle.
Barwa Addax driver Cecotto had been the man to beat around the streets so far this weekend, recording the fastest time in both free practice and qualifying.
He got a clean start, while fellow front-row starter Max Chilton lost out to both Ericsson and Giedo van der Garde before the first corner. Van der Garde had failed to get away initially for the warmup lap, but managed to get going before being passed by the entire train, meaning he was able to re-take his fourth place grid slot.
The gap between Cecotto and Ericsson ebbed and flowed throughout the race, with the Swedish driver often starting to close the gap to his Venezuelan rival, only for Cecotto to respond.
When the compulsory pitstops came, Ericsson was the first to stop on lap 21. However, he was held in his box as van der Garde was coming down pitlane, costing him vital time. He rejoined with a clear track, but Cecotto stopped on the following lap and was able to rejoin safely ahead.
iSport International driver Ericsson quickly closed the gap, only for Cecotto to once again open it up again. Ericsson made one final attack in the last couple of laps, but did not get close enough to make a last gasp move.
That allowed Cecotto to claim victory in his 46th GP2 start, remarkably claiming only his third ever points finish. It comes less than two weeks after compatriot Pastor Maldonado's victory in the Spanish Grand Prix.
Ericsson's second place finish was his first top six finish in what had been an extremely difficult season so far for a man expected to be amongst the title contenders in his third GP2 campaign.
Van der Garde had a fairly quiet run to third – closing on the leading duo in the final stages but still finishing five seconds adrift. It was the experienced Dutchman's 11th start in a Monaco Grand Prix support race, still looking for a victory.
After losing two places at the start, Chilton had to absorb pressure from both Luiz Razia and Jolyon Palmer to hold on to fourth spot during the first stint, while behind Davide Valsecchi was keeping Esteban Gutierrez at bay for seventh.
The pitstop phase mixed everything up however, with points leader Valsecchi staying out the longest of the bunch and benefiting from clean air at the head of the field to steal fourth place.
Chilton finished fifth, rejoining from his stop ahead of Stefano Coletti. The Monegasque driver had yet to make his stop and remained in sixth place until finally stopping with four laps to go. That handed sixth place to Palmer.
Razia slumped from fifth to ninth during the stops, behind Gutierrez. Gutierrez came unstuck trying to put a lap on Fabrizio Crestani – who together with Venezuela GP Lazarus teammate Giancarlo Serenelli had been a devil to get past all race long. Trying to get past at the Neuvelle chicane, Gutierrez launched himself off the kerbing on the inside and into the Armco barrier on the outside, knocking off his front wing. Razia joined the Mexican in pitting and dropping down the order.
This, together with Coletti's subsequent stop for tyres, played into the hands of James Calado and Stephane Richelmi, who had started the race alongside each other on the seventh row. Early stopping Calado followed fellow Brits Chilton and Palmer across the line to finish in seventh place. Richelmi meanwhile claimed his first GP2 points in eighth (albeit a further 16 seconds behind) and with it pole position for Saturday's sprint race in his own back yard.
Nathanael Berthon finished in ninth, with Coletti rejoining from his late stop in tenth to claim the final point just ahead of Tom Dillmann.