The Australian finished second in Monaco to Charles Leclerc after starting alongside the Ferrari driver on the front row.
That followed a similar Saturday performance in Imola, though he started that race fifth following a post-qualifying grid penalty – for which Stella took responsibility.
In Miami, Piastri was similarly competitive and has shown growth in the areas he was focussed on heading into the year – namely tyre management and race pace.
“Oscar is doing very, very well,” Stella proclaimed to Speedcafe.
“Especially, I would say, after we got some information onboard in the early races, about managing tyres, reviewing in particular China, we realised a couple of things.
“We said, ‘we need to adjust these couple of things’, and immediately Oscar was there in terms of pure speed like he’s always been, like qualifying pace.”
Following his debut season, Piastri admitted he felt there was room for improvement in race pace.
Rapid over a single lap, he would fall back from team-mate Lando Norris come the grand prix.
Tyre management in Formula 1 is an art; knowing how and when to push the fragile Pirelli rubber critical in determining the outcome.
It’s a craft impacted by the unfolding race, making it impossible to practice or rehearse on the simulator. Piastri’s only opportunity to hone his skills is in competition.
“Even if you look at Miami, he was behind Lando in qualifying by a little bit, but he didn’t have the full upgrade,” Stella noted.
“We know how much the upgrades are worth, and I can tell you, Oscar did a pretty amazing job.
“He was first row on the grid in Imola and then actually he was demoted for reasons that don’t have to do with him, it was a team responsibility.
“And in Imola, in the race, I was just amazed myself to see like, just putting so much pressure on a Ferrari when we know very well that in Imola when you are one second behind another car, you lose a lot of performance – and he stayed there.”
Stella suggests Piastri had the pace to stand on the podium in Imola, and were it not for the Safety Car in Miami, he’d have appeared in the top three there, too.
Second place in Monaco underscored that belief and the Australian’s ongoing development in his second season of F1.
After eight rounds in 2024, Piastri sits sixth in the drivers’ championship with 71 points, while McLaren is third on 184 – only 92 back from points-leaders Red Bull Racing.