The reigning world champion got his title defence off to the best possible start in Portugal, as he won both the sprint contest on Saturday and Sunday’s main race to open up a 12-point lead in the standings.
Bagnaia took the lead of the feature race at the end of lap two, having started second, but was hounded to the chequered flag by Aprilia’s Maverick Vinales.
Having at one stage been over a second clear, a late charge from Vinales put the Spaniard just 0.687s adrift at the chequered flag.
PLUS: Can anyone stop "changed" Bagnaia as Ducati tightens its grip on MotoGP?
While it looked as if Bagnaia was just controlling his pace to safely get to the end, he later admitted that his medium Michelin rubber had completely faded.
“I was trying to not think too much on the gap, because I was seeing that it was closing,” Bagnaia said.
“I didn’t want to think that I had to push more, because it would have been a problem for the rear tyre.
“I just tried to be as consistent as possible, trying to be a bit faster every lap and it worked very well.
“Just after 15, 16 laps, Maverick was again pushing to close the gap on me and sincerely I was pushing again.
“I was without anymore tyre, so the last two laps I was completely without [grip] and I was a bit in trouble.
“But everything worked well. I was controlling a bit, but I was also forcing a lot.”
Bagnaia is the first reigning champion since Jorge Lorenzo in 2016 to win the opening round of their title defence season, but insists the pressures of being the grid’s main target didn’t cross his mind during the Portuguese GP.
“Sincerely, it was not a thing I was thinking about,” he said.
“Surely, I want to win to be the champion again, but I’m sure that this year the challenge will be very hard with the Aprilia guys and the other Ducatis.
“But we just have to keep our feet on the ground, keep working well, working hard as we were on the whole weekend.”
Bagnaia’s new factory Ducati team-mate Enea Bastianini did not take part in Sunday’s grand prix after suffering a broken shoulder in an incident with VR46’s Luca Marini in the sprint.
Bastianini will miss this week’s Argentina GP too.