Mercedes believes Ferrari's Formula 1 engine is now its equal with it in terms of power, according to Lewis Hamilton.
Speaking on Thursday ahead of this weekend's Bahrain Grand Prix, Ferrari driver Sebastian Vettel claimed Mercedes had a pace advantage of up to 0.4 seconds at the start of the season.
Mercedes has been F1's dominant force in the V6 turbo-hybrid era that started in 2014, but Hamilton said his team had now been caught by Ferrari in terms of engine power.
Asked about the advantage Vettel estimated Mercedes had, Hamilton replied: "I don't have a figure, the team hasn't mentioned a figure to me.
"They said in qualifying we think that we are power-wise equal to them. They made a really big improvement.
"And [the team said] that in the race we might have a slight edge on them.
"It's hard to say from one race, they had a different run profile particularly in the race they were doing something different fuelling wise.
"You'll get a much better idea over the coming races."
Ferrari is understood to have made a 10bhp gain with its 2018 F1 engine having originally set a minimum target of matching its 2017 power.
Its car was quicker than Mercedes on the straights in Australia, although this was aided by running less downforce.
Hamilton still enjoyed an advantage of more than 0.6s in qualifying and was comfortably quicker in the race as well until a mid-race virtual safety car handed Vettel an unexpected victory.
The Briton said he was ready to bounce back this weekend.
"I am still happy with it," Hamilton said. "But I guess it's that I started first and finished second. You never ever want to move backwards.
"That is difficult for us all but everyone in the team felt the same pain. After the race we all got together and sat and had a drink.
"I come here really strong and positive and [have] a good direction about how to move forward. That is why this is such a great team."