Lewis Hamilton believes Mercedes had a "positive" first day of testing in Bahrain as they look to get to grips with their tyre management.
After a minor glitch that prevented the Brit from running for 30 minutes, he ended the day top of the timesheets at Sakhir.
However, the overall aim was not to be fastest, but to ensure that the team can compete with Ferrari over the longer stints.
“Our focus was on advancing our understanding of the tyres and also the rear of the car so that we can improve our long runs – particularly during the race and on the supersoft compound,” said Hamilton after his Tuesday test.
“We came here with a specific goal, so it was positive to get on top of that with the team.”
Hamilton has handed over duties to Valtteri Bottas for the final day of testing on Wednesday, with the track open from 0900 to 1800 local time.