But while his results proved strong, when provided with a car capable of achieving them, the greater focus of his maiden season was learning the ropes.
That extended to shaking the rust off his race craft after sitting out 2022, to understanding when to push and when to manage over a full grand prix distance.
Arguably, the most important lesson was tyre management, given Pirelli's rubber is notorious for having a narrow operating window while being highly susceptible to thermal degradation.
Knowing how and when to use the grip available, versus when to manage the tyre, is a lesson that can only be learned on track.
With limited opportunities during the season for running outside of a race weekend, the post-season test proved the ideal time for Piastri to build his experience.
“Oscar completed 123 laps, including a lot of long runs, which is helpful for the team to understand tyre behaviour and for Oscar to build on maximising performance in the long stints,” explained Hiroshi Imai, McLaren's director of race engineering.
Piastri's task was made simpler by having 10 new sets of tyres available for the day.
For 2024, compounds are set to remain the same, though the range is trimmed from six to five – the C0, which never appeared over a race weekend, will disappear.
“The end of season test is complete. It's been a nice final day on track,” said Piastri of his final day behind the wheel in 2023.
“We've learnt a few new things with the car but also with my own driving, which is always good to work on.”
While Piastri has starred in 2023, his cause has been helped by a car that has made significant strides since the Austrian GP.
Further updates have build on that and saw McLaren rise to fourth in the constructors' championship.
“Hopefully we can take the momentum from the second half of the season into 2024 and start strong,” Piastri said.
“I'm looking forward to the break. I'll be seeing everyone at the factory one more time, and then head off on holiday.”
The Melburnian will first head to Woking and a visit to the team's factory before heading back to Australia for Christmas.
He'll then head back to Europe as preparations for the 2024 season ramp up early in the new year.