Team boss Toto Wolff said Lewis Hamilton's mammoth first day in Spain - when the Briton clocked up 156 laps (more than two race distances) - had helped the team achieve their data gathering objectives in almost one day, allowing them to begin trialling new developments.
"We are having some bits which are slightly unusual – [including] a very innovative front wing," said Wolff. "We are not sure whether they come on the car tomorrow or after tomorrow.
"Our plan for [day one] was to do lots of laps, lots of mileage, and collect data before we head into the next phase - which is looking at performance.
"[The timing of the new parts] depends on the analysis of the data, but certainly there are some things to look at. Certainly when I saw them the first time I was surprised."
Wolff added that the opening day had gone very well for the team, saying: "You shift your expectations and what you are trying to achieve. When it went so well like last year there is still room for progress.
"We had the plan of logging so many kilometres [which] we discussed with Lewis and Nico [Rosberg] before testing. It was an ambitious target but we showed that the team is capable of achieving it - and the driver is capable of holding on."
Hamilton meanwhile described his first day as the 'most impressive I have had', adding: "I've never had a day like [it]. To get in the new car and to have no problems is just remarkable."
Testing continues in Barcelona until Thursday.
First impressions: Lewis Hamilton feeds back on his new Mercedes
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