Valentino Rossi's Moto3 team took a controversial first victory with Romano Fenati at Termas de Rio Hondo in Argentina.
MotoGP legend Rossi has moved into team ownership this season with a pair of Sky-backed KTMs in Moto3 under the VR46 banner for Fenati and fellow Italian Francesco Bagnaia.
Fenati had given the team its maiden podium with second in the preceding race at Austin, and then spent the Termas de Rio Hondo round in the thick of a ferocious lead battle with championship leader Jack Miller, Alex - brother of Marc - Marquez, Efren Vazquez and Livio Loi.
Miller led into the final turns, but Fenati launched his bike down the inside from third place, making slight contact with Marquez and then sliding firmly into Miller, who was pushed wide.
Fenati scrambled across the line to take the win by 0.099 seconds over Marquez, with Miller keeping third ahead of Loi.
Although race direction immediately launched an investigation into the last-lap incident, Fenati was allowed to keep the milestone victory for Rossi's outfit, which is run by former Ducati MotoGP team boss Vito Guareschi.
The officials plan to discuss the clash further with the riders involved after the race.
The result moves Fenati up to second in the Moto3 standings, 17 points behind Miller - who was left furious over the final-lap clash.
The Australian had won both races in the 2014 season prior to Argentina.
The victory ended a two-year drought for Fenati. He had stunned by winning at a wet Jerez just two races into his world championship career in 2012, but subsequently endured fallow times before being selected for Rossi's project.
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