In Friday practice at the Japanese Grand Prix, Nico Rosberg successfully ran the power unit that was removed from his car at the Italian Grand Prix due to reliability concerns, meaning he still has two working engines to use for the rest of the season.
Rosberg had to switch back to a five-race old power unit in Monza after his brand new engine for that race was contaminated by a leak in the cooling system. The five-race-old power unit expired towards the end of the Italian Grand Prix, resulting in Rosberg's retirement, and in Singapore he took his fourth new unit of the season, putting him on the verge of a penalty.
However, the successful running of the original Monza power unit means he is back to having the same amount of engines as team-mate Lewis Hamilton for the rest of the season.
"That was a positive start to that one," Rosberg said. "We tried it the whole day for the first time after Monza to see if it's working okay and it seems to be working fine. Let's see what we can do with it for the future."
Although little could be learned in the wet conditions, Rosberg said Mercedes is not panicking about a repeat of its poor performance in Singapore a week ago.
"I guess yes it would have been important, but then again we are confident because it's the same car that has won all those races prior to Singapore and we haven't changed anything. We still think we are looking good and we are going to be quick and we are not panicking or anything.
"It will be a challenge for everyone tomorrow because it's just one hour to prepare in the dry for everything - let's see if it's dry because we don't even know that - and that's to prepare for everything in qualifying and the race, so it will be intense."