Piastri, entering his second season in F1, bagged fourth place in his home race in Australia last weekend following a team-orders switch to fall behind stablemate Lando Norris.
Norris was faster running on fresher tyres, so the call was designed to minimise the risk of the pair clashing as Stella reckons the overtake on Piastri was already coming “naturally”.
But the Italian engineer still heaped praise on the gains Piastri has made with race pace and tyre management.
Describing Piastri’s execution of the Albert Park race as “very, very good… in a delicate situation” with excessive tyre graining, Stella continued: “Even compared to last year in Australia, or even Japan, and other places at the start of the season, we've gone a long way forward.
“It's extremely encouraging to think that this is only coming at the start of the second season.”
Stella added that the future looked bright for Piastri, given he still had plenty to “cash in”.
He continued: “If you think how much he has to cash in more in terms of improvement, I think it looks very strong for the future from Oscar’s point of view. [In Australia], it was properly complicated.”
Stella credited Piastri’s growing experience, and ability to take in information and learn from scenarios for helping him take the steps forward.
“When I talk about adapting,” he went on, “this is not adapting to when a problem starts. This is adapting to prevent the problem to start.
“You sort of have to understand from the context that, ‘Oh, this context would lead to this problem' before the problem actually manifests itself.
“When you are a rookie, you need to sort of lead into the problem and then realise how you got there.
“So, I think that's the mechanism where he is now much more aware that some conditions will lead to some problems.
“So, when he was driving the tyres around, I think he was feeling that if you overdo the front tyre a little bit then the tyres are not going to be happy from a graining point of view.
“So, you start to understand where is the limit potentially, even going one kph [faster].
“It's a fine tuning, almost like a self-calibration exercise through experience.”
