Piastri said: “The car is an evolution from what we had last year. There’s some things that are different, but there’s a lot of things that still do the same thing as last season.
“From my side, I feel like I have taken a step forward across the board. There’s not been one specific thing that I tried to work on from last year. It’s just been trying to find those last hundreds of a second wherever you can, and that’s been making a difference.
“I’ve still lost out on a few poles by a few hundredths of seconds, so I still have some more digging to do, but that’s been the big difference for me so far.
“There are still some things we’re trying to iron out as a team. The car is clearly very quick, but it’s not always the easiest to get the pace out of, but that was the case sometimes last year.”
He said he was “proud and satisfied” to have been able to claw back the deficit he faced after finishing ninth in Melbourne, where an off-track moment led to him being stuck on wet grass for nearly a minute.
“The championship lead is nice but I’m much more proud and satisfied of the work and the reasons behind why I’m leading the championship than actually the fact that I am leading the championship,” he said.
World champion Max Verstappen did not attend media day on Thursday because his partner Kelly Piquet is due to give birth to their first child.
A Red Bull spokesperson said: “All is well. We will not be offering any further comment at this time in respect towards the privacy of Max and his family.”
The four-time champion is due in Miami for practice on Friday.
