Jack Miller has given the thumbs up to Ducati’s new engine as he marched back the top of the speed trap at Sepang and feels the extra power hasn’t come at the expense of rideability with the GP20.

With Ducati aiming to fightback against Honda’s top speed improvements from last year, it will please the Italian manufacturer to see Miller leading the way with a 331.2km/h on his first day back at the Sepang pre-season test – beating Repsol Honda’s Marc Marquez by exactly 1km/h.

While Miller couldn’t take a clean sweep on the opening day he did lead the Ducati riders with fifth place overall timesheet and just 0.291s off pace-setter Fabio Quartararo, who predominantly stuck to his finely-tuned 2019 Petronas Yamaha.

Miller says he’s dialling in the 2020-specification Ducati but feels the new engine is already showing clear progress.

“The new engine feels good and we had a couple of teething issues with the electronics but we are getting through it and making sure the little problems are sorted,” the Pramac Ducati rider said. “There are not too many. As I said the bike is relatively good and I felt good, my first flying lap was a 2m 00.9s or something so I can’t really complain.

“The bike is working really well and I felt good on it straightaway. The balance we had to adjust a little bit there but the rest is good.

“It feels good, we were on top and the next Ducati was a little bit down so they must not be tucking it in. I definitely know my corner speed isn’t so great through Turn 14, I am struggling through there but the rest is going alright.”

Miller also feels the GP20 chassis he tried out is an improvement but held back on a further evaluation until he’s had more time to fully assess his 2020 package.

“I only got to ride the [2020] bike for a day in November but I liked the gains then and I’ll second that again coming back here. We have still got a lot of work to do but the initial feeling is pretty good,” he said.

“We have gained a little bit in turning, just improved the steps that made it a massive difference between the ‘17 to the ‘19 and the ‘19 to the ‘20. The step isn’t massive but another step in the right direction. I feel we are improving step-by-step.

“The power is good, the way the bike is ridable, it’s not too aggressive, sometimes when they increase power you can lose the rideability of it especially with the Michelins so we need to be very smooth with the tyres.

“It was more on working with the initial setup of the bike, understanding what we need to do and keep going on that.”

The Sepang pre-season test continues until February 9.