With just under two hours of running remaining, power was lost at the Bahrain International Circuit.

It saw garages plunged into darkness and the circuit’s floodlights switch off, forcing officials to show the red flag.

Power was restored to the pit lane after around half an hour, but it took longer for the flood lights – and therefore track action – to come back to life.

Running only resumed with 50 minutes of the scheduled program left, prompting teams and officials to agree to an additional hour make up for the interruption.

It was the most dramatic part of an otherwise routine day punctuated by Norris going fastest and spins for Liam Lawson and Isack Hadjar.

Lawson lost the Red Bull exiting Turn 2 during the opening session of the day after tagging the apex kerb at the left-hander.

The New Zealander flat-spotted a set of tyres as the RB21 screeched to a halt broadside on track but otherwise escaped drama.

Later in the day, Hadjar dropped his Racing Bull exiting Turn 4 shortly after the lunch break.

Conditions in Bahrain were unseasonably cool and, at times, blustery, making the drivers’ task even harder.

Red Bull boss Christian Horner suggested Lawson’s spin was a result of the wind, which presumably accounted for a handful of moments Max Verstappen experienced when he got behind the wheel.

Further, it suggested the RB21 is a handful, or at least more suspectable to winds than others.

McLaren enjoyed a trouble-free morning with Oscar Piastri logging 66 laps before Norris took over.

However, Norris’ session started slowly with as he spent much of his first two hours in the garage.

When Speedcafe questioned the team, McLaren insisted the delay was simply a result of changes to the car for the afternoon session.

Norris logged only four laps in the first 90 minutes of running after the break while attention was focused on the rear of his McLaren.

When he did finally manage a time, he quickly recorded the third fastest lap of the day, going fastest after the power cut.

On track, the McLaren looked planted and compliant, reaffirming its tag of early favourites – though only a whisker clear of Ferrari.

Beyond the power cut, the day went to script for most, with plenty of aero rakes and flo vis paint on display as teams worked to correlate their virtual data with the real world, a process that will continue over the next two days.

Day 2 of F1 pre-season running begins at 18:00 AEDT.

Pre-Season Test: Day 1 Results