Ducati came into last year as the favourite to win the championship, but the early races of its campaign with its 2022 bike were troubled.
A strong post-season test at Jerez in 2021 gave way to a difficult pre-season in 2022, particularly with the new engine, with Bagnaia ultimately switching to a hybrid 2021/2022-spec unit for the start of the season.
Ducati was able to get on top of its early-season woes to give Bagnaia a bike with which he could win seven grands prix and ultimately the championship.
After finishing day two of this weekend's Sepang test fifth overall, Bagnaia says Ducati is already close to matching the potential of the bike he won the championship on and has not suffered the same problems it did last winter.
"At Jerez, in the last test of the 2021 season, it looked like the new bike was incredible," Bagnaia said.
"Then we moved to here [Sepang] and the feeling wasn't the best. Then we worked a lot and everybody knows the story.
"This year, from the first exit with the new bike, I feel great.
"I feel we are very close to the 2022-spec. So, considering the 2022-spec had four years of development and already to be so close [with the 2023 bike] is a good thing.
"For sure we learned from our mistakes."
Bagnaia also noted that Ducati has found yet more top speed (it topped Saturday's speed charts at 336.4km/h), something "we don't need" but that hasn't come at the expense of handling.
He also feels acceleration – a key issue of the full 2022-spec engine – has been improved.
"Now I will say something that everyone will have fun with, because we grew the top speed today with the new engine," he added.
"It's something we don't need, but it's always helpful. And we didn't do any damage in terms of riding, handling, because the bike from last year was already at a really great level.
"So, the new engine demonstrated that it is higher, so now we have to reach the same level or even better in the acceleration.
"Today we did a good step in front, especially in the wet because in the wet the acceleration has to be smooth.
"So, I think we can be happy, we could reach the level of the 2022-spec bike tomorrow."
