Early days, but Red Bull's RB16B has pace and reliability as Max Verstappen tops the timesheets and completes the most laps as testing gets underway.
Yes, yes, yes, we don't know the fuel loads or tyre strategy, but Red Bull will be heading into its debrief this evening feeling a lot happier that its Mercedes counterparts.
Though conditions were good this morning, albeit a little blustery, by the afternoon the track was engulfed in a sandstorm, which left the track surface like a skating rink and visibility at a minimum.
While Mercedes was frustrated by a gear shift change this morning and sand and poor handling in the afternoon, Max Verstappen quietly got on with the job in hand, completing 139 laps and setting the best time of the day.
The day was not without its problems for the Dutchman, who had a spin and a couple of minor offs earlier, but this appeared to be more about the conditions than any significant issue with the car.
"We had a very positive day and managed a lot of laps even though the track conditions were quite difficult," said Verstappen. "It was very warm with a lot of wind and we know the degradation is always high around here so I'm very happy with how it went.
"We aimed for this number of laps and when you can complete a full programme like this the team can also be pleased with the information we have.
"We don't need to talk about pace yet and it isn't really a discussion until we get to Q3 at the first race weekend - it's only then you see the real pace in all the cars. The main thing is that the car felt nice to drive, so it's a positive start."
"Today went well," added head of race engineering, Guillaume Rocquelin. "The conditions were pretty difficult and very windy, especially in the morning. It calmed down a bit in the afternoon but a lot of dust had been kicked up and it was very hazy and quite difficult to run in.
"In terms of objectives we're really pleased, as we had a target in terms of the number of laps we wanted to get through and a fairly busy run plan and we were able to stick to both.
"Lap time is not what it's about at this stage and I don't think Max will be getting too pumped up about being at the top of the timesheet on day one. What's more important is that we were able to follow the plan and do the laps.
"For Sergio tomorrow, the conditions should hopefully be a little better. It's not supposed to be quite as hazy, but the wind is likely to still be quite strong. The plan will be pretty much the same for Checo, so fingers crossed we're looking forward to another good day.
It was a good day also for McLaren, with Daniel Ricciardo topping the timesheets this morning and Lando Norris finishing second this afternoon, the Woking pair completing 91 laps between them.
For the most part it was a trouble-free day for the team, which is now powered by Mercedes, though a late off following a lock-up from Norris led to the deployment of the VSC.
"It was really good to get back out in the car for my first proper session with McLaren," said Ricciardo. "I was able to push the car a little bit and get more familiar with it. It was a smooth morning, everything ran well and that's all you can ask in testing - you want reliability on your side and the team back in Woking has done an awesome job of giving us a great start on day one.
"We got a good amount of runs and laps done, with a focus on getting more and more familiar and comfortable in the car. The plan for the next few days is similar, we're aiming to leave here feeling ready to go for the Bahrain Grand Prix. Happy days."
"First of all, very happy to be back in a Formula 1 car," added Norris. "It's my first time putting the MCL35M to the test in the dry. It's quite a shock to feel the speed of a Formula 1 car again, it's been a while since I've had that sensation. It was a good shock and it felt nice to be back, but not as nice with the conditions today. The second half of the day was very dusty and windy which made it tricky, so it wasn't the easiest first day back in the car.
"We spent the session going through our test programme, making sure there are no problems with the seat and that I'm comfortable in the car. We've got some things to work on from that side over the next couple of days. We'll sit down and review everything this evening, but it's been a solid first day. Thanks to everyone both here and back at the factory for all the hard work and making it such a smooth first day's running."
"It was a productive first day of testing," said team boss, Andreas Seidl. "The conditions were a bit special due to the wind and sand on the track, but actually this didn't affect the run plan very much as we could still compare data from run to run and from both drivers. We didn't have any major issues today, only small things to fix here and there which is normal on the first day running a new car. But it's only day one, and we'll keep monitoring as we accumulate mileage on the car.
"We were able to run through our planned test items - Daniel running in the morning and Lando in the afternoon - with both drivers getting an early understanding of the car. We now need to optimise the remaining two days with preparation for the first race being shorter than ever, so we need to try and be as efficient as possible."
Like Verstappen and Red Bull, Esteban Ocon had a solid day in the Alpine, the Frenchman completing 129 laps and posting a best time just 0.472s off the pace.
The Frenchman began his day with aero correlation work, with a front tyre rake fitted to the car for the opening runs. With the initial laps running smoothly, he pushed on and ran to his programme as planned with 55 laps completed before the lunch break.
Despite the change in the weather, Ocon was immediately out of the garage for the afternoon running, continuing to increase his lap count to over a century midway through the session. On the C4 tyres, he improved his lap-time to a 1:31.416.
"Everything went well today," said the Frenchman, "and it was definitely a good first day back at school! It was a solid one for the team, we completed the programme with ease and we even had time at the end of the day to do pit-stop practice with the team, which was quite nice as it meant we could get ourselves back into race situations.
"We put in some decent laps today and we learned everything we set out to achieve and that's exactly what you need during test days. We faced all kinds of conditions as well: heat this morning then strong gusts and a sandstorm this afternoon, so pretty much everything except rain. That was interesting but we did what we needed to, and I look forward to driving the car again later this weekend."
Lance Stroll spent most of the afternoon propping up the timesheets as he persisted with the same set of hard tyres, but when he finally made the switch to Pirelli's prototype rubber he improved to fourth.
This morning, teammate Sebastian Vettel set his best time on the prototype, the German finishing 13th overall.
The day was not without its problems for the Silverstone-based outfit, with Vettel stopping at the end of the pitlane with an unspecified issue earlier and Stroll missing the first ninety minutes of this afternoon's running. Nevertheless between them they completed 97 laps.
"It was a very productive morning," said Vettel, "and really the first opportunity we've had to truly put the AMR21 through its paces. As I expected, there are a lot of new things to learn. I'm working with a different power unit compared to the past, which means there are lots of new procedures involved. Then there's a new steering wheel with all its buttons, and different braking too - so I'm very aware that there is a lot to learn.
"The important thing is that I know where we can improve. It was tricky on track because it was so windy out there; you could see that everyone was fighting for grip. Today wasn't about lap times, it was about finding a good balance in the car and getting a true read on it while collecting lots of important data, which we managed by running 51 laps in the morning session. I am looking forward to going over the data tonight and continuing to make progress with the car. I think we can say it was a good first day for the AMR21."
"It was a good start," added Stroll. "Conditions were really tricky out there and you could feel the effect of the wind on the run down to Turn One, and you could feel the tailwind in certain corners too. I don't think anybody found it easy out there.
"It's early days to be making judgements on the car and we have to remember there is a cut in downforce, which you can feel in the car, and there are new tyres too. The important thing is that we made an encouraging start and it felt good to drive the AMR21. We spent the majority of today doing aero mapping and collecting plenty of useful data.
"It's great to be back in the car and really feeling the energy of the team. It is a new beginning as Aston Martin and I am enjoying working with Sebastian and getting to know how he operates. All in all, it's been a productive session and I definitely enjoyed my day in the AMR21!"
Check out our Day 1 pre-season test gallery from Bahrain, here.