Mercedes has completed a two-day test at the Varano circuit ahead of its full switch to Formula E next year.
Both Stoffel Vandoorne and Gary Paffett were present at the test, as the team set 218 laps around the Italian circuit on Monday and Tuesday.
"It was great to get back behind the wheel of a Mercedes-Benz-powered car," said Paffett, who is the reigning DTM champion with Mercedes.
"It's obviously different from any Mercedes I have driven before, but it has been a fantastic test. I think that the professionalism and the skill of the engineering within the team is exceptional.
"There is no doubt there is a lot of work to do, but the test has been really positive. We've got some really good mileage under our belts, and the car has been very reliable. It's been a good couple of days and I can't wait to get back in the cockpit."
Vandoorne added: "It's been good to track the evolution of our powertrain since the shakedown I drove in some time ago.
"This is all part of our long journey. There is still a lot of work ahead of us, and everyone is aware of that.
"But I would say that the first impressions are very good. The basics are right and everything seems to be working well. That's what matters at this point. It has been a positive start."
The sixth season of Formula E gets underway in November later this year, while there are just two races left this season - a doubleheader finale in New York.