Pierre Gasly takes the wheel of the AlphaTauri AT02 in the morning
Max Verstappen deep in concentration as he prepares to leave the pits in his Red Bull RB16B
Something catches the eyes of the McLaren drivers as they pose for a grid photo in the morning. Daniel Ricciardo (R) took the wheel first
A spectacular puff of smoke emitted by Verstappen's RB16B as he locks up
The resplendent blue of the Alpine A521 shines at Sakhir, with Esteban Ocon taking over on day 1
Lewis Hamilton dons his shades for the class of '21 photo. Team mate Valtteri Bottas was hampered by a gearbox issue in the morning
Carlos Sainz poses with his new team mate Charles Leclerc ahead of testing. Leclerc took the wheel in the morning
The splash of green certainly stands out on the Ferrari SF21
Sebastian Vettel on track in the new Aston Martin AMR21, after his switch from Ferrari
Kimi Raikkonen takes the new Alfa Romeo C41 out on track
Daniel Ricciardo has swapped Renault for McLaren for this season
New Haas drivers Mick Schumacher and Nikita Mazepin pulled the covers off the new VF-21 in the Bahrain pitlane before testing got underway
Bottas managed just 1 lap in the new W12 before gearbox trouble confined the car to the garage in the morning session
Development driver Roy Nissany was at the wheel of the new look Williams FW43B on Day 1
Plenty of the team were running the aero-rakes on their cars as they gathered data on their first day of proper running
Bahrain is hosting pre-season testing this year, instead of Barcelona
Mick Schumacher put the Haas VF-21 through its paces in the morning session
Mercedes revealed their 'secret' new floor, which they had not shown at the car's launch, when the W12 hit the track
Pierre Gasly prepares to head out on track
Max Verstappen leaves the garage ready for another run in the new RB16B
What's that coming over the hill? It's Roy Nissany in the Williams FW43B
Sainz prepares to take on the sandstorm
Norris's papaya MCL35M complements the orange hues of the Bahrain desert perfectly
Hamilton took over for Mercedes in the afternoon, but Verstappen was the one setting the benchmarks with Red Bull
Tsunoda made his public AlphaTauri debut and we caught a glimpse of the AT02 under the floodlights
Verstappen set more than 122 laps over the day with the highest mileage and lowest time
Ocon's Alpine shone under the floodlights on Friday as he finished third
BAHRAIN, BAHRAIN - MARCH 12: Max Verstappen of the Netherlands driving the (33) Red Bull Racing RB16B Honda kicks up sand during Day One of F1 Testing at Bahrain International Circuit on March 12, 2021 in Bahrain, Bahrain. (Photo by Clive Mason - Formula 1/Formula 1 via Getty Images)
Stroll (L) and Sainz (R) have a mini duel in the desert
The floodlights bathe Ocon's car in a healthy glow
Norris finished second overall by the end of Day 1, with 45 laps under his belt
Giovinazzi got his first go in the Alfa Romeo C41 on Friday, after Raikkonen began the morning testing session