Sky Sports F1's Martin Brundle says Mercedes' "relentless" pace and reliability "can't be ignored" after the Barcelona shakedown.

Lap times were effectively irrelevant during the five-day event in Spain as the teams completed as many laps as possible to test reliability and gather data for the new 2026 cars.

Although Ferrari's Lewis Hamilton was fastest by one tenth from Mercedes George Russell, the Silver Arrows had the most mileage with 500 laps with Ferrari in second on 440 laps.

"Mercedes never really aced a ground-effect car. They had porpoising, they never really got it right. They didn't understand the car's performance a lot of the time, and they didn't really know why," Brundle told Sky Sports F1 ahead of the final days' running where Hamilton had a strong Friday.

"Clearly, they look like they've sort of aced this completely different set of regulations. But we need to see what it's like on normal track temperatures. It's going to be about (power) regeneration and filling their battery back up, but of course, they'll regen as well as any other Mercedes-powered car, probably Ferrari-powered car too."

Mercedes dominated Formula 1 following the last power unit regulation change in 2014 and will look to build on their strong shakedown at the two Bahrain tests on February 11-13 and February 18-20.

Brundle says it's "too early" to judge any teams' concept but thinks Mercedes have found "the sweet spot" in the very early stages of F1's new era.

He said: "You might have a car that just fires its tyres up brilliantly on a cold day and then overheats them on a hot day, which is a problem we've seen Mercedes have before.

"I do think we need to stay calm on it, but you can't ignore the relentless pace and reliability that they've had. So, clearly, they've got a really good, cohesive package."

Aston Martin completed just 65 laps in Barcelona - the least of the 10 teams that ran there with Williams missing the entire event.

But, when Aston Martin rolled their car out on the penultimate day in black, it gathered plenty of attention as the car design was different to the rest of the grid, with aggressive bodywork to redirect airflow.

Adrian Newey had a major say in the 2026 car design after he joined the team last year and Brundle thinks we will need to be patient to see if Newey has worked his genius again.

"Adrian's cars tend to be quite homogenous in their beautiful, sweeping air-flow to them, you often see that with all of his cars. There doesn't appear to be as many bits hanging off his cars as on some others," he said.

"It's really hard undercut on the sidepod, and we've seen different interpretations, some sidepods, front wings, across the board, which is unsurprising with such new regulations.

"We've got to assume Adrian has come up with some good ideas, but does he know enough about the Aston Martin wind tunnel, and their digital wind tunnel? Will he get correlation? Has he got the right people around him to interpret his brilliance? That's a tall order straight out the box.

"Adrian was saying to me that Honda are having to play catch up because they were leaving and then they came back in. So, there's some question marks there, and we'll to wait and see. But you just know that Adrian will have a vision of how to maximise these regulations."

Fernando Alonso said the "car is responding well" after his first day in the new car on Friday and it was a "tremendous effort" to get some running in Barcelona.

Alonso added: "Some of the teams did filming days and shakedowns in the beginning of January and then the whole weekend here in Barcelona, but for us it was the very first day."

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