Charles Leclerc says Ferrari was caught out by McLaren's top speed in the Azerbaijan Grand Prix, as he labelled his rival's flexible rear wing a "controversial" design.
The Monegasque driver was locked in a race-long battle with Oscar Piastri for victory in Baku last weekend, but his hopes of a triumph were dashed just a few laps from home when his rear tyres faded.
Having reflected on the factors that cost him the win, he admits that one of the most important was the fact that, after losing the lead to Piastri, he and Ferrari never anticipated the McLaren's top speed to be as high as it was – especially when DRS was not open.
That is why Leclerc did not choose to aggressively defend the front spot when Piastri made his critical pass of him on lap 20.
"It was a good move," he said. "However, as I said when I saw him going on the inside, I knew he was there. I knew it was an opportunity for him to get past, but I was not more worried than that.
"I knew that he could take the lead, but I also knew that I was at the beginning of the warm-up of the tyres, and I didn't want to push on them, so I didn't want to start going stupid in terms of how defensive I would get.
"However, I was wrong because obviously his straightline speed was really, really strong and after that I never had the opportunity to pass again."
He added: "I don't think on the attacks there was anything better I could have done. I could have done a better job defending. However, again, I didn't know how quick they were on the straights after that."
The repeated reference to Piastri's straightline speed comes amid great intrigue over the behaviour of McLaren's rear wing in the Baku event.
As was revealed by rearward-facing onboard cameras, the upper element of the McLaren rear wing appeared to flex back on the straights and open up the slot gap to help reduce drag. It quickly earned the tag of acting like a 'mini DRS'.
Its design has prompted some rival teams to seek clarification on its design to better understand what the limits are in terms of flexible bodywork.
Ahead of the Singapore GP, the FIA has said it is examining evidence it obtained on the wing from Baku to decide if it needs to make any response.
It is understood that Ferrari team principal Fred Vasseur has some strong opinions on the matter, and he is due to speak at an official FIA press conference at the Singapore GP on Friday.
Leclerc said the team had discussed the matter internally, although he did not wish to get too drawn into the matter.
"Yes, [there is] definitely a dialogue that we've already had," he said, when asked for his thoughts on the wing.
"I mean, I think Fred will go on that matter a bit more into detail, but from what I've been told, it's controversial to say the least. So, yeah. I'll leave that here and I'll let Fred comment on it a bit further."