Piastri saw his advantage over teammate Lando Norris trimmed to 25 points after a messy few days in Baku that included crashes in both qualifying and the race.
The 24-year-old misjudged his braking in Q3 and hit the Turn 3 wall, jumped the start on Sunday and then crashed into the Turn 5 barrier on the opening lap, ending his race.
Stella, who previously worked alongside Schumacher, Fernando Alonso and Kimi Raikkonen during his Ferrari years, was quick to put the setback in perspective.
“I’ve worked with multi-champion drivers and in a season, every season, even the most dominant, even by one of the best drivers in the history of Formula 1, like Michael Schumacher, I have seen events like this,” he said.
“The most you take away is the learning because things become, for some reasons, difficult – and as soon as you misjudge the grip available, you get highly punished.
“So, a one-off for what has been probably the most solid driver in this season… is no surprise, no exception that we should be worried about, because this has happened to pretty much all champions – even the ones with the best track record.”
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Despite Piastri’s rare mistakes, Stella praised his ability to recover quickly.
“I think one of the strongest features of Oscar is how rapidly he learns, how rapidly he improves, and how he can come back stronger,” he said.
“That’s why he’s been so successful in every category and I think that’s exactly what will happen in his Formula 1 career, and we will see it in the remainder of the season.”
Not everyone sees it so calmly. Former world champion Jacques Villeneuve believes Piastri may already be feeling the heat of the title fight.
Reacting to the Australian’s qualifying crash in Baku on his Instagram story, Villeneuve said: “Piastri put it in the wall, the championship leader. He’s been driving erratically this weekend, so it looks a little bit tough.
“He’s feeling the pressure, [but] saved by the fact that Norris messed up his laps as well.”
Villeneuve had previously warned that a sizeable points cushion could lead to “second-guessing” and “extra stress” that causes mistakes.
Seven-time grand prix winner Juan Pablo Montoya also suggested Piastri might subconsciously alter his approach in the final rounds.
“We’re starting to see a side of Oscar we’ve not seen before – I don’t think Oscar has seen it before,” Montoya said on F1 TV.
“Whether you like it or not, mentally, you are going to change your approach because you’re going to start double-guessing yourself.”
Piastri’s Baku exit came as Max Verstappen claimed a second straight victory for Red Bull, further tightening the title picture.
But Stella remains convinced his driver will respond in Singapore and beyond.
“I had a chat with Oscar and his mind is already fully functional, processing, he’s already into ‘that’s what I’ve learned, I look forward to the next one.”
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