The 2026 Formula 1 season got off to its unofficial start on Monday in Barcelona.

Monday kicked off five days of private, closed-door testing ahead of the 2026 F1 season. The grid will look very different this season, and not just because Cadillac is joining the sport as the 11th team. F1 has implemented a host of new technical regulations, aimed at making the cars lighter, smaller, and more agile. That includes changes to the distribution of the power units between the Internal Combustion Engine (ICE) and the battery, as well as the active aerodynamic systems on both the front and rear wings.

To help the teams prepare for the new season F1 scheduled three different testing sessions, kicking off this week with the closed-door “Barcelona Shakedown” at Circuit de Barcelona-Catalunya. Teams are allowed to run on three of the five days, but that does not mean every team will be in attendance. Williams, for example, announced last week that due to a developmental delay they will sit out this first testing session.

One team that did participate on Monday? Mercedes, and according to their post-session media report, the Silver Arrows are “happy” with what they saw from the W17 on the first day.

“We are happy with how today went overall,” said Andrew Shovlin, the team’s Trackside Engineering Director. “The main thing we are looking for in the early running of any new car is to make sure we can get plenty of laps in. That enables us to get into the learning of our programme in subsequent days. Today was all about understanding the car, therefore, making sure it stabilised at the correct temperatures, and ensure we could do our long runs. It is positive that we were able to achieve that.”

Young Kimi Antonelli took the morning session, completing 56 laps while using three different tire compounds. After starting his run on the Intermediate tire, Antonelli switched to the C3 Soft compound, before finishing his program on the C1 Hard tire.

The second-year driver called it a “productive” first day.

“It was nice to be back in the car this morning and, more importantly, we’ve had a productive first day here in Barcelona. There is lots for us to learn with these new machines so it’s important that we complete as much mileage as we can and build our knowledge. The team at Brackley and Brixworth have done a great job to get us to this position, developing and building a car that has been able to complete over 150 laps on its first proper day of running,” said Antonelli.
“It is early days though. There will be things we discover in the coming days that we can improve but that is the point of testing. For now, though, the package overall feels good, and we will look to build on this start over the following two days of running we’re allowed here in Barcelona.”

Veteran George Russell took the afternoon shift, completing 95 laps during his portion of the program. While he was “pleased” with what he saw from the W17 he also noted the work done by Mercedes’ rivals.

“It’s great to be back out on track driving an F1 car once again! The cars looked really cool out on the circuit and that’s positive for our sport. They are quite different for us as drivers but, once you get your head around it, driving them is quite intuitive. It’s enjoyable being behind-the-wheel and I think there’s a lot for fans to look forward to with these new regulations,” began Russell.
“We are pleased with our day, but I’ve also been impressed by several other teams too. The Red Bull power unit has completed a lot of laps which, given that it’s their first engine they’ve built, means they’ve clearly done a good job,” continued the veteran driver. “Haas also managed a similar amount of running to ourselves, so the Ferrari power unit has also put together plenty of mileage. It’s not quite how it was in 2014! The sport has evolved so much since then and the level, in every single aspect, is so high now.”

The worst-kept secret in the paddock is that Mercedes expects to be on the front foot when the season begins in earnest. Whether that is due to what the team has put together behind closed doors, or just carryover expectations from the last time F1 saw an extensive a regulation change as we are going to see this year, remains to be seen.

But for one Monday in Barcelona, the Silver Arrows are happy with what they saw.