Other newcomers in action were Alpine’s Jack Doohan and Haas’ Ollie Bearman, who both made substitute appearances last season, while Lawson completed his first official laps as a fully-fledged Red Bull racer.
However, the talk of the paddock before the green light switched on at the end of the pit lane was Lewis Hamilton, who completed the next step in his monumental Ferrari move.
IN PHOTOS: Every 2025 F1 car on track during pre-season testing in Bahrain
As the morning progressed and various run plans played out on different tyres and fuel loads, Antonelli wound up with the quickest time – having clocked a 1m 31.428s on medium rubber.
Lawson was just over a tenth adrift in the newly-launched RB21, despite a wild moment and half-spin through Turn 2, with Alex Albon putting his Williams third and Yuki Tsunoda placing fourth for Racing Bulls.
Hamilton attracted plenty of attention as he strolled through the paddock in Ferrari gear and took to the track in the SF-25, working his way down to a time some four-tenths slower than the man who took his place at Mercedes.
