Miller was second-fastest in Friday practice for the 2021 British Grand Prix, although his personal best 1:59.829s was 0.512s slower than the pace set by Yamaha's Fabio Quartararo.
Silverstone was dropped from the 2020 calendar due to the COVID-19 pandemic, meaning this weekend's British Grand Prix takes place two years after the last.
Danilo Petrucci was lead Ducati rider in seventh in that race, while Miller finished a position further back after his holeshot device did not disengage at the first corner.
The Queenslander was buoyed by his latest Friday practice performance on the flowing English circuit, which hardly suits the traditional strong points of the Desmosedici.
“First of all, it was good to be back out on the Silverstone track,” he said.
“It's a proper old-school race track, so a lot of different style of corners.
“The track's in good condition. Really cool to sort of compare my feelings I remember from 2019 to 2021 and how much the bike has developed over that time, over that period, and the positives of the bike – how much, especially in the first sector, through the sequences of left-rights, it's a big step there.
“It was one of the moments where you reflect on how the bike's going and how much headway we've made with this bike. It was a really good day, I felt comfortable from the get-go.”
Miller's practice showing is not the first time that the Ducati's improved handling has been shown off this year.
Asked about the physicality of his bike at Silverstone, Miller said it was “the main thing” of the GP21's turning.
“Your timing is much easier to get right in that first sequence, but also the physicality of the actual change of directions, the bike is doing it much easier,” he explained.
“You're not having to force it so much, put so much input into the handlebars to achieve the same result.
“So, sure, it's definitely better and it makes me excited to head to places like Texas. Also maintaining the tyres because you don't have to keep the lean angle so much, but also on the race pace.
“It's a lot easier to be more precise, you're able to get your timing correct pretty much every lap.”
Free Practice 3 starts at 18:55 AEST, followed later in the evening by FP4, Qualifying 1, and Q2.