The Frenchman, who started fourth on combined practice times, immediately shot to second at the start of the Losail race before surging past the Suzuki of Andrea Iannone and into the lead later on the opening lap.
He had built an advantage of 1.6 seconds over the chasing group before losing the front of his 2016-spec Yamaha M1 at Turn 2 on the seventh lap of the race, ending his charge.
Zarco said he was sure a podium finish would have been possible if not for the error, but said he accepted the risks associated with pushing hard from the start.
“We can say that [it was] a rookie mistake,” he said. “I just wanted to go, and I said that if you make the decision to go fast and push, you can find the limit. I accept what I choose.
“Starting from the second row, I wanted to use this opportunity to be quick in the pace like the top riders.
“I could see I was feeling good compared to them, so I’m just happy I could overtake the riders and then take the lead and try to go away.
“The feeling was good, I didn’t want to push more, but it means that I was close to the limit and [I was] just a little bit wide at Turn 2.
“It’s a shame. For sure it was possible maybe to take a podium or more.”
Soft tire gamble
Zarco was among those to opt for the soft rear tire option, and the Frenchman said he wanted to take a gamble as he had “nothing to lose” on his debut MotoGP race outing.
“I said to the guys ‘I want to play for this’, like in poker, for the soft tyre,” he said. “I was maybe not the only one and seeing that the race was 22, [then shortened to] 21 and then 20 laps.
“I said ‘why not try it, I have nothing to lose.’ I’m a smooth rider and it was possible to keep [the tyre] good.”
The Moto2 champion added that his star performance had made him reconsider what could be possible later in his debut MotoGP campaign.
He said: “My coach said, ‘You need to improve your feeling and still need to learn things, but keep training hard and yes – you can dream about victories and podiums.’
“I need to learn this new category, there are some small things that you need to control a little bit more. I didn’t do it here, but I need to play again to make it happen for the future.”