Pierre Gasly and AlphaTauri set the pace as F1's official pre-season test got underway at the Bahrain International Circuit.
Gasly's time of 1:33.902, set on the Soft C5 tyre, put him around half a second clear of Ferrari drivers Carlos Sainz and Charles Leclerc (both on the Medium C3).
Mercedes pair George Russell and Lewis Hamilton (both C3) were ninth and 11th respectively in the upgraded and 'sidepod-less' W13, with Red Bull's Sergio Perez (C2) splitting them before a late spin.
The full times and tyre compounds are listed below.
Video: AlphaTauri present their new F1 car!
Check out AlphaTauri's new F1 challenger, the AT03, which was presented to the world during a special launch ceremony.