Mercedes DTM team believes it's "on a good path" after testing

The championship's most-successful manufacturer has failed to win a title since Paul di Resta's 2010 triumph, claiming 11 race victories against Audi and BMW in those four seasons.

New HWA CEO Ulrich Fritz has overseen a major restructure of the Mercedes programme, including the homologation of a new C-Coupe, which Christian Vietoris first raced at Zandvoort's penultimate round last September.

Capping a positive pre-season, Mercedes F1 reserve driver Pascal Wehrlein topped the final day of testing at Oschersleben last week, with Gary Paffett and Robert Wickens second on the other days.

"It was pretty promising," Vietoris told AUTOSPORT. "We were roughly half a second faster than last year's pole position time, also the long runs we did look good.

"But it's always hard to judge. After [the first test at] Estoril, I would have said Audi was clearly on top, but at Oschersleben they were not super fast.

"So it's really hard, but we made a step forward, that's for sure.

"We've got a lot of new people in the team, the car is reacting to the changes we can do, which wasn't always the case last year.

"If we do some changes on the car it actually goes faster, so that's positive.

"I think now we just need to wait and see where we are in Hockenheim, but it looks not too bad at the moment."

Fritz, who stepped into the role just under 12 months ago following Gerhard Ungar's departure, was also buoyed by the testing progress.

Work on the new car has focused on overcoming the predecessor's high-speed corner and tyre management shortfalls.

"In the end what you saw on the car, mainly aero-related, was developed throughout the last races of last season, until everything had to be homologated in Zandvoort," Fritz said.

"We are on a good path and it's difficult to judge performance because everybody is running different programmes and schedules in testing, so it's difficult to judge who is where.

"In the end, this is something we will be able to answer after the first round in Hockenheim."