World champion Marc Marquez won the Argentina MotoGP on Sunday ahead of bitter rival Valentino Rossi.
Honda rider Marquez claimed his 45th career victory in the elite class, finishing 10 seconds ahead of Rossi on a Yamaha.
Andrea Dovizioso, who won the season-opener in Qatar, was third on a Ducati.
Marquez, chasing a sixth MotoGP world title, now leads the 2019 championship after two rounds of the 19-race series.
As Marquez was rarely threatened in Sunday's race, the wheel-to-wheel action was being ratcheted up behind him as Rossi and Dovizioso switched places 12 times.
But 40-year-old Rossi had the last laugh, pouncing on a Dovizioso error on the last lap to take second place on the same circuit where 12 months ago he had collided with Marquez and crashed out.
Australia's Jack Miller on a Ducati-Pramac was fourth, Alex Rins of Spain on a Suzuki was fifth ahead of Ducati's Danilo Petrucci.
Earlier, Italy's Lorenzo Baldassarri won the Moto2 race with Remy Gardner, the son of 1987 world 500cc champion Wayne Gardner, taking second place.
Baldassarri, on a Kalex, made his push for victory four laps from the end at Termas de Rio Hondo to deny 21-year-old Gardner of Australia with Alex Marquez of Spain in third.
It was a first world championship podium for Gardner.
The 22-year-old Baldassarri leads the world championship having also won the opening round in Qatar earlier this month while Gardner is second, 17 points behind the Italian.
"It was a good race and important victory for the team," said Baldassarri.
"I knew that I couldn't battle at the start, I had to manage the tyres so I concentrated on the end of the race."
Spain's Jaume Masia, on a KTM, claimed a maiden Moto3 victory, edging out South Africa's Daryn Binder and Tony Arbolino of Italy on the line.
Having started the race on pole, Masia regained the lead on the last lap, erasing the misery of his first-lap fall in Qatar.
"It's incredible. I have to thank my team and my fans," said the Spaniard.
Japan's Kaito Toba keeps the overall world championship lead after a 10th place finish on Sunday to follow his victory in Qatar.
He has 31 points with Italy's Lorenzo Dalla Porta in second on 29. Masia moves into third spot, a further two points back.