Two-time premier class champion Stoner was one of several test riders that took part in the three-day private test that precedes the start of official pre-season running on Sunday.

Sharing duties with fellow Ducati tester Michele Pirro, the Australian was originally scheduled to ride on Wednesday and Friday, but weather conditions meant he ended up riding on Thursday and sitting out Friday.

Stoner was the first rider to try out the GP18, the bike that factory riders Jorge Lorenzo and Andrea Dovizioso will campaign this year.

Speaking to Motorsport.com, the 32-year-old said he feels the Italian manufacturer has succeeded in mitigating the weakest points of the 2017 machine, a lack of mid-corner speed and engine management.

"Weather conditions changed our plan, but we could take some benefit during two hours on Wednesday and on Thursday afternoon," Stoner said.

"My conclusion is that we’ve done some steps forward in terms of chassis and some things regarding the engine. So far everything is positive, we haven’t found anything negative.

"I think it is very difficult to satisfy the requirements of a MotoGP rider, but I must say that we are going in the right direction. From now on, it’s a matter of getting more experience and going forward.

"I can’t wait to know what Jorge and Dovi think about the new bike after trying it. Improving the weakest points of the past will be a huge step."

Lorenzo and Dovizioso will get their first taste of the 2018 bike on the first day of official testing on Sunday, having run with a modified 2017 bike at Valencia and Jerez last November.

Sepang testing "makes no sense"

After inclement weather disrupted Stoner's programme on Wednesday, the Australian suggested that Sepang was no longer fit for purpose as a pre-season testing venue.

Resurfaced back in 2016, the track now takes considerably longer to dry out after rain than it had in the past - and while modifications were made in July to combat the issue, Stoner feels the situation remains sub-optimal.

"One of the conclusions we have drawn after this test is that these track conditions make such a mess of things," he said. "The required time to dry out after the rain is too much.

"The work done here has been less than effective. Previously, we would come to Sepang during the pre-season because if it rained, the track would dry out in 20 minutes.

"With these conditions it makes no sense to test here."

Translation by Irene Aneas