Niki Lauda believes the start of the 2016 season will provide a decisive insight into the battle Mercedes will face against rival Ferrari.
The former triple World Champion's outlook for the new season remains cautious as he considers the Scuderia's margin of development progress to be more important than that of Mercedes.
"Ferrari can develop its chassis, it aerodynamics and also its power unit more easily than us," Lauda told the Gazetta dello Sport.
"We were very strong in preparing the hybrid engine at the outset with all it’s implications. But at this point our margin for improvement has reduced.
"That said we have more experience with hybrid than the others and we know where to intervene to hold onto the margin we had right up to the last race.
"I think the first three races of 2016 will tell us how the whole 2016 season is going to go."
Ferrari's heavy restructuring process which was initiated at the end of 2014 is still a work in progress but nevertheless yielded three victories this past year, and Lauda expects the Italian outfit's challenge to ramp up even more in the coming months.
"Ferrari is Ferrari again; you can see it in the way they have gained ground from year to year," the Austrian concluded.
"Vettel has given us something to think about; he’s been quick, he’s won, his hunger has grown. They are already on the right track to make more progress."
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