Charles Leclerc said he pleaded with Ferrari to stay out on medium compound tyres while leading Sunday's Hungarian Grand Prix before a pit-stop for hard tyres wrecked his victory hopes and claimed "there's always something going wrong."
The 24-year-old Monegasque driver, who finished sixth as Max Verstappen won to increase his championship lead to 80 points, said the decision had surprised him and cost him the race.
With only nine races to go after the scheduled summer break, it may also have cost him any hope of the drivers title.
Asked to explain why Ferrari had made the decision, he said: "I don't know yet. I need to speak with the team and understand the thought behind putting the hards because I felt very strong on the mediums.
"Everything was under control and then, for some reason, I don't know why, we need to go onto hards.
"I said on the radio I was very comfortable with the mediums and that I wanted to go as long as possible with those tyres because the feeling was good, but I don't know why we took a different decision."
Leclerc had worked his way through to lead the race by mid-distance, having passed pole-sitter George Russell of Mercedes, and was five seconds ahead when Ferrari reacted to Red Bull's decision to bring in Verstappen on lap 39.
After running on two sets of mediums, Leclerc needed a change of compound and would have preferred a set of softs later in the race to set up a fast finish.
He said the timing of his second stop was critical, saying that he felt Ferrari had reacted to Red Bull instead of staying with their own strategy.
"I think my second stint should have been longer," he explained. "The first stint was the right moment to stop and we did the right choice there, but on the second stint there, I don't know exactly why we cut it short and went on the hard.
"I'm pretty sure that this was a call to put us under pressure, but I don't think we should have reacted to that because then it was a snowball effect for us and we lost a lot more than we should have."
Leclerc has suffered a string of misfortunes this year, suffering from engine problems, lack of reliability, botched strategy and an error of his own that have combined to give champion Verstappen an easy defence of his title.
"A race like this is frustrating and we need to get better as a whole," he added, maintaining his composure.
"It feels like there is always something going wrong – reliability, mistakes, whatever.
"We need to be better at putting a weekend together. Now, we will try to use the few days we have to reset, but also try to analyse and understand where we need to be better and what we can do to be better because it is extremely important."
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