Lewis Hamilton says the way his Mercedes Formula 1 car felt in practice for the Australian Grand Prix was almost a "night and day" difference compared to pre-season testing.
Hamilton was more than half a second clear of his nearest rival in both Friday sessions in Melbourne, a change from pre-season testing when Mercedes was regularly slower than Ferrari.
After the two weeks at Barcelona Hamilton claimed he had not got his car into a good window, while team-mate Valtteri Bottas admitted the team had hard work to do to unlock the W08's potential.
Hamilton, who led Bottas in practice one and Ferrari's Sebastian Vettel later on, said those issues meant the performance on Friday in Australia was "kind of a relief for all of us".
"Coming into today we had no idea where we would stand," he said.
"It was kind of a night and day difference to how the car felt on the last day of testing.
"The car's feeling good so I got through all my running and I got a good understanding of the tyres on low and high fuel, which puts us in good stead for tomorrow.
"There's things we struggled in in the test and things weren't quite perfect in the car. [Here] everything's performing at its optimum, which is great.
"It feels amazing and that's, to be honest, surprising."
Despite his encouraging start, Hamilton said it would be foolish to rule out Ferrari - although he admitted it looked as though Mercedes was clear of Red Bull.
"I think the Ferraris are obviously still very, very fast and strong, much stronger than they've ever been, so we have to keep a close eye on them," said Hamilton.
"They might not have the power turned up or whatever it may be, so we'll see tomorrow.
"Red Bull have taken a great step into this weekend, but it seems that we're currently as strong or a little bit stronger than them."
BOTTAS NEEDS TO WORK ON QUALIFYING PACE
While Hamilton had a serene Friday, his new team-mate Bottas had a scruffy pair of sessions ahead of his Mercedes debut.
The Finnish driver lost time on ultra-soft tyres in both sessions and admitted it was those performance runs that he needed to address for Saturday.
"Yeah, it is a big gap, but I'm not worried yet," Bottas answered when asked if he was surprised by Hamilton's advantage.
"It's Friday practice, and my first proper practice in a race weekend with the team.
"I am allowing myself time to work on things and I'm sure tomorrow I can make a step forward and continue from there.
"Looking at the race, it's looking OK but the short runs are my priority tonight, to get that fixed and try and find a bit more pace for qualifying."