Max Verstappen concluded F1's pre-season test in Bahrain at the top of the timesheet, the Red Bull driver lowering the benchmark to 1m31.720s to finish 0.695s clear of the field.
The Dutchman, running at the wheel of a revised RB18, overhauled early pace setter Charles Leclerc to lay down a marker ahead of next week's season opener at Sakhir.
Verstappen relied on Pirelli's softest C5 tyre to comfortably edge Leclerc who set his fastest lap on the C4 compound.
Fernando Alonso who topped the mileage chart with 122 laps, delivered to Alpine a satisfactory third fastest time, the Spaniard also fitted with C4 rubber on his best flyer.
Bahrain Pre-Season Test - Day 1
|1||Max Verstappen||Red Bull||1m31.720s||C5||53|
|5||Valtteri Bottas||Alfa Romeo||1m32.985s||C3||68|
|7||Sergio Pérez||Red Bull||1m33.105s||C4||43|
|10||Sebastian Vettel||Aston Martin||1m33.821s||C4||81|
|11||Guanyu Zhou||Alfa Romeo||1m33.959s||C4||82|
|16||Lance Stroll||Aston Martin||1m36.029s||C3||53|
The afternoon session was about to conclude its first hour when Verstappen finally took to the track, with Red Bull rolling out an RB18 that featured revised sidepods and front wing.
The Dutchman jumped to the top of the timesheet after 90 minutes, with a time that was 0.460s clear of Sergio Perez's morning benchmark and over a second ahead of the rest of the field.
However, with an hour and a half left on the clock, Leclerc sprung to the top, edging Verstappen by 0.230s. But the Red Bull driver eventually reclaimed the top spot with an effort that clearly demonstrated the pace and the efficiency of Red Bull's updated RB18.
Behind the top three, George Russell who had taken over from Lewis Hamilton lined up fourth in the pecking order despite a W13 that still looked very much on the edge.
A late flyer by Valtteri Bottas earned the Alfa Romeo a spot among the top five, the Finn clocking in just ahead of AlphaTauri's Yuki Tsunoda.
Perez's morning best was good enough for P7 overall, while Haas' Mick Schumacher eclipsed the fastest time set by his teammate Kevin Magnussen, the young German claiming ninth ahaed of McLaren's Lando Norris.
Alex Albon and Nichola Latifi were the only other drivers to take to the track in the afternoon, with their best efforts placing then respectively P14 and P15 overall.
Like yesterday, Haas was awarded an extra hour of running to cap its pre-season test in Bahrain.