Ferrari offered a clear indication that its under-performance in Melbourne was a one-off, with Charles Leclerc and Sebastian Vettel topping the time sheet in Bahrain's first free practice session.
The Scuderia duo was just under a second clear of Mercedes' Valtteri Bottas, while Lewis Hamilton was further adrift in fourth and Red Bull's Max Verstappen was fifth.
Bahrain marked a return to a more traditional circuit for F1 after Melbourne Albert Park, with expectations that the second round of the 2019 world championship will perhaps offer a clearer picture of the pecking order.
But the main focus at the outset was on Ferrari and undercovering any suggestion that's relative under-performance Down Under was a one-off.
As a reminder, on the tyre front, teams are supplied this weekend with Pirelli's hardest compounds: the C1, C2 and C3.
With qualifying and Sunday's race taking place in cooler evening conditions at Sakhir, FP1 wasn't considered a representative session, while activity was also limited in the first hour by the track's dusty granite surface.
However, when the action did pick up, Ferrari took command, with both Vettel and Leclerc running comfortably clear of their Mercedes rivals for most of the session.
Bottas outpaced Hamilton in the day's session as the reigning world champion appeared to struggle with the handling of his W10.
Red Bull Racing's Max Verstappen and Pierre Gasly lined up immediately behind the Mercedes duo while McLaren's Carlos Sainz was 'best of the rest', followed by renault's Nico Hulkenberg.
Toro Rosso's Daniil Kvyat and Alfa Romeo's Kimi Raikkonen rounded off the top-ten.
At the other extreme, Williams predictably made up the rear, 3.8 seconds ff the leader's pace, pointing to another complicated weekend for the British outfit.
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