Daniel Ricciardo was fastest but there was trouble at Mercedes as Formula 1 testing began in Bahrain.
Reliability was always going to be crucial with just three days of running before the first race in two weeks time, but the reigning champions managed just six laps in the first four hours on Friday.
The reason, a gearbox problem on the W12’s first lap on track which cost Valtteri Bottas over three hours as Mercedes replaced it.
Currently, the Finn is set to hand over to Lewis Hamilton for the afternoon, but after the lost track time, it is not inconceivable the plan might change.
Also having gearbox problems was Mick Schumacher in the Haas, as the German only managed 15 laps in the VF-21.
At the other end of the scale, Honda enjoyed a very productive morning as Pierre Gasly topped the distance charts with 74 laps for AlphaTauri and Max Verstappen sat third with 60.
Both of them were also within half a tenth of Ricciardo’s best time for McLaren, a 1m32.203s, some five seconds slower than Hamilton’s pole time in Bahrain last year.
Of course, that’s a reminder that performance is the last thing on teams’ minds at this stage, but conditions were not exactly ideal as strong winds and a sandstorm blowing in from the desert as the morning progressed.
Behind the top three, Esteban Ocon was fourth for Alpine and Charles Leclerc fifth, though the Ferrari driver did cause a late red flag for a so-far unspecified reason.
A glitch put Kimi Raikkonen 20 seconds clear of the field on the timing screens at one point in the Alfa Romeo, but the 2007 world champion ultimately ended sixth after that was resolved.
Sebastian Vettel enjoyed a solid start with 51 laps for Aston Martin in seventh, though did come to a halt at the end of the pit-lane at one point.
You’ve seen the #AMR21 out on track. Now it’s time to climb aboard. ?
[Sorry about the sound… Seb was so quick he broke the mic. ?] pic.twitter.com/dtviy7kKyv
— Aston Martin Cognizant F1 Team (@AstonMartinF1) March 12, 2021
Roy Nissany, the only non-race driver testing week, was eighth in the Williams as Schumacher and Bottas brought up the field after their gearbox woes.
Another four hours of running awaits on Friday afternoon into the early evening with only Verstappen, Ocon and Nissany staying in their cars.
But more important will be how much running Mercedes can recover to avoid ending the day somewhat on the back foot.
Full results from the morning can be seen below: