Marco Bezzecchi cruised to a maiden Moto3 win in a damp Argentina Grand Prix, while a failed gamble on slicks saw Jorge Martin lose his championship lead to second-placed Aron Canet.
A slight drying line had appeared for the start of the race, with pole man Tony Arbolino gambling on slicks, while Martin dived into pitlane at the end of the warm-up lap to switch to dry tyres.
Off the line, Valentino Rossi protege Bezzecchi eased into the lead from second the grid, while the slick-shod Arbolino dropped to 19th by the end of the opening lap.
One second clear by the end of the first lap, Bezzecchi effortlessly built up a comfortable advantage on his Prustel GP KTM – the Italian over six seconds clear of the field by mid distance.
Martin, who exited the pits almost a minute down on Bezzecchi, quickly began to set the pace throughout the field, the Gresini rider dipping into the 1:57s and lapping two seconds quicker than the leader by lap 12.
Behind Bezzecchi, Fabio Di Giannantonio, Aron Canet, rookie Juame Masia and Adam Norrodin debated second spot.
In the closing stages, Canet broke away from Di Giannantonio and Masia, while Enea Bastianini closed in on the battle for third.
Di Giannantonio survived a collision from Masia at Turn 5 on the penultimate lap and closed down Canet over the final lap, but the Estrella Galicia rider held firm to secure second ahead of the Gresini rider and Bastianini, while Bezzecchi eased to his debut win and KTM's first since Mugello last year.
Martin fought his way through to 11th in the final laps, but has slipped 10 points adrift of new standings leader Canet, while Arbolino managed his best ever grand prix result in 10th.
Norrodin held fifth for his best result ahead of rookie Alonso Lopez, with Qatar podium finisher Lorenzo Dalla Porta heading Niccolo Antonelli and early podium contender Gabriel Rodrigo.
Masia was joined by Dennis Foggia on the sidelines, after the Sky VR46 rider crashed out of seventh at Turn 5 with three laps remaining. Albert Arenas and Foggia's teammate Nicolo Bulega – who also gambled on slicks – dropped out as well.
