Formula 1's first morning of official pre-season testing ahead of the 2022 campaign has ended with Ferrari top of the timing sheets, but it is the new 'sidepod-less' Mercedes W13 that is the talk of the paddock.
Lewis Hamilton's car left the garage sporting a new-look sidepod design in the Sakhir sunshine, vastly different to any design deployed by their rivals ahead of the new season.
The design has been dubbed 'sidepod-less', with the cooling inlets so narrow that the car appears to be without them entirely. The car also features wings mounted above where the cooling inlets would typically be, leaving designers across the paddock looking on with interest.
Fierce rivals Red Bull, which also adopted an aggressive sidepod design for day one of testing in Barcelona, say they will be looking closely at the design.
Red Bull team boss Christian Horner told F1 TV midway through the morning session: "It's obviously a fairly different concept, but that's for the aero guys and the designers to get into."
Leclerc fastest, new Mercedes fifth
Despite the new design, Hamilton ended the session as fifth fastest following a morning that saw teams running through various testing programmes, from which little information can be gained in terms of pace.
Leclerc's Ferrari, which so often topped the timing sheets in Barcelona, ended the morning on top once again with a 1:34.531 on the Medium C3 tyre, just under four seconds slower than the fastest time on day one of 2021's Bahrain test.
Alex Albon placed second with a 1:35.217 (Soft) during an impressive morning for Williams that saw them lap consistently quick late on in the morning.
Sebastian Vettel's Aston Martin ended the session third with a 1:36.166 (Medium), ahead of Sergio Perez's Red Bull in fourth with a 1:36.247 (Medium).
Hamilton, in his radical new Mercedes, put in a 1:36.365 (Medium) to complete the top five.
You can stay up to date with all the action from Bahrain in the dedicated RacingNews365.com live blog.
F1 Podcast: All you need to know after the first pre-season test
At the end of the first pre-season test of 2022 in Barcelona, Dieter Rencken and Thomas Maher discuss the on- and off-track developments so far.