McLaren has been told by Renault that they have found "a lot of kilowatts" of power in the development of their engine for the 2019 season.
The French constructor could not do enough to save its relationship with Red Bull for next season, but if its claims are to be believed then it will mean that they have made decent progress in its quest to be on a level playing field with Mercedes and Ferrari.
This news will also be encouraging for McLaren, as they are trying to get back to the front end of the grid after some of the worst seasons in their illustrious history.
Speaking to the media on Wednesday, McLaren boss Zak Brown said that Renault were optimistic: "They are telling us that they are very pleased with their winter progress. They have found a lot of kilowatts, and think they will be in the ballpark.
"It is not appropriate for me to quote the numbers they have given us, but I think they feel they are going to be very competitive next year. There is a lot of cautious optimism, but we clearly don't want to get ahead of ourselves," he added. "We have done that before and we are not going to make the same mistake twice.
"So it is a very head down approach. Development is going well, and we are on track with what we are wanting to achieve. But ultimately obviously we have no idea where the competition is, other than speculating. Everyone plants their different stories: they either want to under play it or over play it. I don't think we will obviously know until we get to Barcelona.
"We are pleased with the progress we have made. We have done things differently, everyone is working well together, so it feels like a more quiet confidence. But we are on our toes. We know this is an important year for us to show progress and that comes with some exciting nervous energy."