The factory Ducati star was on the back foot after qualifying in sixth, while title rival Jorge Martin romped to pole but was worse to follow in the opening laps.
Bagnaia was firmly passed by Martin’s team-mate Johann Zarco, then found himself caught up in a feisty tussle between the Frenchman and another satellite Ducati of Alex Marquez, leaving him ninth.
It took the Italian until lap 5 of 13 to finally clear them both and, after closing down on the group ahead, he finished in the wheeltracks of VR46 Academy colleague Marco Bezzecchi.
“I missed the start a bit, then I lost a lot of time with Zarco, and then with the battle between Johann and Alex Márquez, which in that moment was quite useless, considering the amount of time we lost,” Bagnaia said.
“They were overtaking like it was the last lap, and it was useless!
“When I was able to get in the front, I was like 1.6 seconds behind Marc Márquez [then in sixth].
“We managed to close the gap and to control everything perfectly. My feeling was again so good on my bike. And I'm happy with the tyre consumption, with the feeling, but finishing 7th in a moment where you are so fast and strong is not good for us.
“So for tomorrow, I have just to improve my pace in the first laps to stay away from battles that make us lose too much time.”
Saturday was the first time since the Indonesian Sprint that Bagnaia had lost points to Martin.
Alex Marquez: ‘You want to play? We play’
Alex Marquez agreed that the fierce early fight with Zarco had been 'useless' but wasn’t going to back down.
“I overtook Bezzecchi and had Marc in front, it was the time to overtake Marc and go forward. But after that, I had the fight with Zarco where I lost maybe 1.5s.
“There was not really sense about that battle. But he was really aggressive - and me too. Because I say, ‘OK, you want to play, we play’”
The Gresini rider, who finished eighth, added: “I completely agree with [Pecco]. I mean, I was just trying to overtake Bezzecchi, but I don't know why, Johann touched me really hard two times. I don't know for what. He was trying to [overtake] me and then he showed in the end that he was not faster than me.
“But it's normal. Everybody wants to be more in front. Everybody wants to gain positions. It’s racing, and it was a nice battle. But I completely agree with Pecco, that it was for nothing.
“So it's important to not be involved in those situations because the Sprint race is all about details. I think in the long race we will have more opportunities. If we make really good first laps we can fight for the podium. If not, we will be like today, like P5 to P8. So we need to be really intelligent and try to manage that situation. To be a smart.”
Zarco, who eventually finished just behind Alex Marquez, also felt the early fight had cost him.
“I was pretty fast at the beginning of the race, and this was great to be able to fight. But I've lost time with Alex Márquez, and then my front tyre got overheated, and I could not fight any more,” he said. “But the pace to be in the top 6 was possible.
“But still, my style sometimes is a bit too different, and there are some areas where I cannot really fight.
“The entry of the corner, the last part of the brake, is not my advantage. He [Alex Marquez] was strong in that area, then when the front tyre overheats, it's even worse.
“I'm happy, at least I took 1 point, that is better than nothing.”