McLaren had a slow start to the 2023 season when the MCL60 missed development targets pre-season.
Stella and McLaren Racing CEO Zak Brown pulled no punches in their honesty ahead of the campaign and admitted the squad was behind the eight ball in the early races.
However, an aggressive development approach resulted in a significant upgrade at the Austrian Grand Prix.
Fitted to Lando Norris' car, it was a crucial moment for the team as it would define the team's future one way or the other.
“Difficult to mention one in particular,” Stella said when asked for his standout moment of 2023 on the KTM Summer Grill.
“I just go by instinct and feeling in trying to answer your question, and as I do so, what comes to my mind, almost in a visual way, is the early laps in Austria.
“We had, in Free Practice 1, Lando was in the new car and Oscar was in the previous car, and I could see in telemetry that Lando, thanks to the new car, he was able to carry quite a lot more speed in the corners.
“I remember thinking to myself ‘this looks good'.
“So that was a good memory, good feelings which, thankfully, was confirmed by lap time and it was confirmed then by results.”
The Austrian Grand Prix was the first of back-to-back races, with McLaren pulling out all the stops to have another example of the upgraded car ready for Piastri just a week later at the British Grand Prix.
Alongside Austria, that event is another fond memory and key moment for Stella.
“We had a McLaren in the lead,” he recounted.
“We had two cars that should have finished on the podium, because Oscar's podium was missed just because of the timing of a Safety Car.
“That was kind of confirmation we are strong, we are on a good path.
“There was still good development ongoing that they would have seen the light later in the season.
“So that's two highlights, if you want, of this turnaround.”
McLaren went on to finish fourth in the constructors' championship, having languished in 10th and last following the Bahrain Grand Prix.
From Austria, it was the second most prolific team after the all-conquering Red Bull Racing, highlighting the dramatic gains made by the team.