Alfa Romeo head of trackside engineering Xevi Pujolar has revealed Kimi Raikkonen led the call that secured points in "hero-to-zero" conditions at the Russian Grand Prix.
Raikkonen, who had missed the preceding two races before Sochi after testing positive for Covid-19, used all of his experience to secure a second top-10 finish in the last three races he has started.
Whilst competitors were left stranded on slicks as rain fell in the closing laps, the 41-year-old Finn timed his stop to perfection to eventually finish eighth.
Asked how the decision to pit was made, Pujolar explained: "That was asking him if it was too wet to be out on slicks and it was his call to come in.
"For us, it is very difficult, especially when you don't have wet at the same level on all parts of the track, so we were ready and asked him continuously what was going on.
"It was his call, he was getting close to the pit entry and we asked what he thought. He said it was getting too much, so inter[mediate tyre]."
Mercedes and McLaren showed fine margin of wet-weather call
Mercedes overruled Lewis Hamilton's pleas to stay on slicks in a move that ultimately won him the race, while McLaren's Lando Norris missed out on his maiden F1 win by staying out too long.
Explaining the circumstances, Pujolar added: "I think in all the conditions when the track is getting more towards wet, you need to rely more on the driver.
"Obviously, the forecast is also important but then at one point, if the driver is telling you he is not able to keep the car on track, you need to react.
"It is not an easy call because you only have a few laps until the end of the race and you can say 'Okay, it is only raining on one side of the track. If I can keep the car on track, losing four or five seconds, how quickly can you go on inter or will you destroy the inter on the dry part of the track?'
"I don't think you have a straight answer. It worked well with us with Kimi, another day, it will go in another direction.
"It will go from hero to zero very quickly in these kinds of conditions. I will say from wet to dry then maybe it is more the team's decision and dry to wet is more towards the driver.
"It was a particular struggle with a few laps towards the end of the race, we were not sure if it was a shower maybe on one side of the track, but obviously at one point it was very wet on that side, too difficult to stay on track."