Francesco Bagnaia wins Japan MotoGP ahead of championship leader Jorge Martin
The Italian defending world champion Bagnaia overtook pole-sitter Pedro Acosta on the first lap at Motegi and stayed in front to finish 1.189sec ahead of Martin with Marc Marquez third.
Ducati rider Bagnaia also won Saturday's sprint race to leave Japan 11 points closer to Pramac's Martin than he was at the start of the weekend.
It was Bagnaia's eighth Grand Prix win of the season, his best-ever tally.
It was also his first victory at the Japan MotoGP.
"Jorge today was much stronger compared to the other day so I was just trying to manage the gap," said Bagnaia.
"It wasn't easy today to remain constant with the tyres. I think the pace was incredible in the first 10 laps.
"We have to move on to the next one with the same ambition, the same strategy and try to continue like this," he added.
The next race is the Australia MotoGP at Phillip Island in two weeks' time.
Martin, who is chasing his first world title, started from 11th on the grid after crashing in qualifying.
He finished fourth in the sprint race.
Martin said he was happy with his Grand Prix runner-up finish despite a late surge that saw him eat into Bagnaia's lead with a handful of laps remaining.
"For sure, being that close to Pecco (Bagnaia) I wanted to give it a try, so I never gave up," said Martin.
"I pushed until the end. Then, three laps to go I had some moments so I said 'OK Jorge, it's time to relax and think about the points'."
Spanish rookie Acosta was on pole for the first time in his MotoGP career but he slid out with 21 laps to go while trailing Bagnaia in second.
Acosta had also crashed out in the sprint race.
Italy's Enea Bastianini finished fourth and stayed third in the overall standings, two points ahead of Spain's six-time world champion Marquez.
Under cloudy skies but with the rain holding off, Acosta held off Bagnaia on the first turn but the Italian took the lead soon after.
Martin went from 11th to fourth before the first lap was over.
Martin overtook South Africa's Brad Binder and then moved up to second when Acosta wiped out two laps later.
Martin pushed for the win but Bagnaia had the composure to see out the victory.
"Congrats to Pecco, he's the master in managing the tyres," said Martin.
"I did a good job, I think. Nice first laps, and I'm super happy with this second position."
Marquez and Bastianini were locked in a titanic tussle for third but Marquez held on to his position.
"It was a difficult weekend but we're on the podium again so super-happy," said Marquez.
Italy's Franco Morbidelli was fifth and Binder was sixth.
Spain's Maverick Vinales, who started third on the grid, was another who crashed.
