With track conditions at Istanbul not drying up enough to be suitable for slicks, leaders Valtteri Bottas and Max Verstappen elected to pit around lap 36 for fresh inters to see them through to the end.
But Leclerc, who had been shadowing Verstappen prior to the pitstops, chose to stay out and initially it appeared he had done the right thing as his rivals failed to close up on him.
However, as the track dried out, Leclerc began to suffer more and more as the tyre performance dropped off – and in the end he was forced to pit on lap 47 having just lost the lead to Bottas.
Falling back behind his main rivals, Leclerc struggled with graining on the new inters and then lost the final podium place to Sergio Perez before coming home fourth.
Although a top-three place had been up for grabs, Leclerc said he was completely comfortable with Ferrari’s tactics – and felt that it was not actually much of a gamble to stay out.
“I had all the info I needed at that time, and once Valtteri pitted [from the lead], I was asking quite a lot on the radio, ‘okay what are the lap times on the new inters?’ explained Leclerc.
“For the first five/six laps we were actually more or less in line with the pace. So for me it was clear that it was not just rolling the dice.
“I think I was quite, and we were all, confident with that choice. But it was a bit of a strange race with the new inters for six or seven laps. They had like a graining phase, and once you went through the graining phase then you were finding a lot of pace again.
“That’s basically exactly what happened. So no regrets on my side.”
Charles Leclerc, Ferrari SF21, arrives on the grid
Photo by: Steven Tee / Motorsport Images
Ferrari team principal Mattia Binotto added that his team’s decision to keep Leclerc out had been shaped by its evaluation of Carlos Sainz’s used rubber when he stopped for new tyres himself.
Binotto said that there were no doubts that the used inters would get to the end without failing – but the only uncertainty was whether they would perform as strong as new rubber.
“Obviously we had the pit stop done with Carlos, and we knew how much rubber was left on his tyres at that moment,” said Binotto.
“Knowing that data, we believed that we could have finished the race, at least in terms of being safe in that respect.
“So we knew that in terms of safety, all the conditions were there. Then it was a matter of performance.
“As Charles said, at the time when we stayed out, the performance was okay. But then the track changed, it was drier, and we had to come in.”
Once the pace on the old inters had gone, Leclerc felt that there was no benefit to staying out as he would have ultimately lost out to the chasing cars anyway.
“It would have been very, very difficult without stopping to be honest,” he said.
“The rear tyres were very difficult to handle in the last four laps before my pit stop, and that’s why we did the pit stop actually.
“I struggled a lot with rear locking and that pushed me to do some mistakes. I don’t think [we would have come home] better than where we finished with the pitstop.”