In the opening stages of the race the Canadian built a lead of around 10s on the wets, but once he switched to Inters his problems began,
In no time at all, there was a clear sense of urgency in the voice that only a few laps earlier appeared to have everything under control.
Clearly struggling, the Canadian was called in for another set of the green-banded tyres, but things rapidly went from bad to worse, as he was gradually picked off by Hamilton, Verstappen, Vettel and Leclerc, finishing the race a distant ninth, over seventy seconds behind the winner.
"I don't know what happened, I don't understand," he admitted at race end. "We had so much graining on the first set of intermediates. We decided to pit, we were losing seconds a lap.
"I just don't know where that graining came from, it just happened instantly," he continued. "It grained again, massive graining, and no pace.
"We'll have to look into it, it was pretty terrible today."
Teammate Perez, who finished second to Hamilton, made only one stop, his Inters lasting 48 laps, just two laps less than the world champion's stint on the green-banded tyres.
"It's just frustrating that you're in the lead by ten seconds, and then all of a sudden you finish ninth," sighed Stroll. "I don't understand how that happens. I mean I do, it's graining, but we just need to look into why it hit me so much harder than the other car.
"I’m not so sure why."
Check out our Sunday gallery from Istanbul, here.