Piastri, entering his second season in the top flight, 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 praised on the gains Piastri has made with race pace and tyre management, saying the FIA F2 champion has “gone a long way forward” with McLaren.
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.”
Source: Autosport