Mercedes is planning to ramp up its performance in the coming days of testing with some "slightly unusual" updates set to feature on the new W07 before the end of the week.
Mercedes kicked off the pre-season with reliability testing, racking up an impressive 156 laps of the Circuit de Catalunya without any major issues on day one. Hamilton was over 0.4s off Sebastian Vettel's best time, but Ferrari's advantage might not last long as a new front wing and other updates are expected to come to the track in the coming days.
"I think we are having some bits which are maybe slightly unusual," team principal Toto Wolff said. "We're not sure if they will come on to the car tomorrow or after tomorrow, it depends on how the analysis of the data from today goes. But certainly some things to look at. Certainly the first time I saw it I was pretty surprised."
Wolff said the opening day was all about checking reliability before the performance testing starts on Tuesday.
"It's pretty true that you shift your expectations and what you're trying to achieve. When it went so well like last year there is still room for progress and our plan for today was to do lots of laps and lots of mileage to collect data and check various systems and correlation before we head in to the next phase and this is looking at performance which is going to happen starting tomorrow or after tomorrow."