George Russell was the first out of the pitlane and onto the Bahrain International Circuit, potentially a subtle message from Mercedes that they mean business this season.
Only ten minutes into the session, the red flag was out as Felipe Drugovich pulled over to the side of the track only a few seconds into his first run.
This was down to an electronics issue but when he finally got back on track, it meant that all ten cars set a lap in the test.
Red Bull’s Max Verstappen topped the times early in the session before Ferrari’s Carlos Sainz went over a second faster within the first hour of the test.
Alex Albon became the first driver to reach what is the equivalent of a full race distance, which in Bahrain is 57 laps.
With an hour left of the session, Verstappen, Sainz and Russell all reached the half-century mark in what proved to be a rather straightforward test to this point.
With just under 15 minutes left in the session, the yellows flags were out which lead to a virtual safety car, but this wasn’t for any on-track issue, but rather a pre-planned systems test.
The afternoon session took some time to get underway, with Verstappen the only driver to remain in the car after the break.
The Dutch driver spent the afternoon setting some blistering times as he tested the limits of the RB19.
With the sun starting to set at the Bahrain International Circuit, the floodlights came on to give us the familiar feeling of the Grand Prix.
Verstappen and Sainz still remained top of the standings when the clock ticked under an hour and a half remaining.
Fernando Alonso impressed in his maiden Aston Martin outing, going second on the timesheets, narrowly behind Verstappen.
Sergio Perez and Lance Stroll were the only two drivers contracted for this season to not get any track action, with Perez doing the full day on Sunday and Stroll being replaced by Felipe Drugovich following his cycling injury.
Here is how the leaderboard looked at the end of the day’s running: