Newly-crowned world champion Lando Norris kept his McLaren top of the order on the first official day of Formula 1 preseason testing for 2026.
Norris' quickest time, a 1:34.669, set with just over an hour of the day left, went 0.129 seconds quicker than Max Verstappen, the man who chased McLaren's drivers all the season-ending Abu Dhabi Grand Prix in last year's title race.
Norris, carrying the number one on his car this year for the first time in his career, shared driving duties with teammate Oscar Piastri as McLaren made a solid start to the first three-day test in Sakhir.
Verstappen completed a mammoth 131 laps of the Bahrain International Circuit, which will host the 57-lap Bahrain Grand Prix in April, giving further reason to think Red Bull's newly built engine project is in a good place reliability wise.
Ferrari's Charles Leclerc finished the day third, albeit over a second down on Norris' quickest time.
Headline times are still not completely representative at this point of testing, but it was curious not to see a stronger showing from the heavily favoured Mercedes team.
After impressing with the mileage accumulated over F1's private Shakedown event in Barcelona last month, Mercedes had a more ordinary day, with preseason favourite George Russell and Kimi Antonelli combining for 75 laps either side of the lunch break. Neither set particularly eye-popping times during their time in the car either.
The German manufacturer will hope to pick up the mileage counter over the remaining two days -- usual preseason logic would dictate that a better competitive picture will start to reveal itself come the end of this first week.
McLaren's Zak Brown believes the top of the order will be too close to call.
"I think we can't come to any firm conclusions," Brown told Sky Sports. "If I had to go Vegas [to bet on it], it looks like the big four are the big four, kind of hard to tell in what order.
"Mercedes were very strong in Spain. Max has done some great lap times around here. But it kind of looks like the grid is in a similar position."
Lewis Hamilton drove in the morning for Ferrari and he and Leclerc combined for 126 laps over the course of the day.
The day featured a first proper look at the Williams car which missed the Shakedown test entirely.
Alex Albon and Carlos Sainz ensured the team had a good start to its season, logging a huge 144 laps between.
Having started the season on the back foot, the productive day will have been a huge morale boost to Williams.
Aston Martin's much-anticipated car, the first designed under the leadership of Adrian Newey, also featured, although Lance Stroll only completed 36 laps over the course of the day.
Aston Martin was late to the Shakedown, completing only one meaningful day of running out of a mandated three, but team boss Newey suggested at the team's launch on Monday the team is happy to be starting the season on the back foot, with fresh upgrades already in the pipeline.
F1's new teams also featured -- Cadillac duo Valtteri Bottas and Sergio Perez clocked 104 laps, while Nico Hulkenberg and Gabriele Bortoleto completed 118 between them for Sauber.