McLaren principal Andrea Stella has laid bare growing frustration with engine supplier Mercedes after the season opener in Melbourne exposed a stark performance gulf between the works team and its customers.

While Mercedes swept to a dominant one-two with George Russell leading rookie Kimi Antonelli, McLaren’s reigning world champion Lando Norris trailed home fifth, more than 50 seconds adrift. Team-mate Oscar Piastri never even made the start, crashing on his way to the grid after a sudden spike in power pitched him into the barriers.

The deficit has sharpened focus on how much information Mercedes High Performance Powertrains are sharing with their customers under Formula 1’s radically revised 2026 regulations, which place an even greater premium on energy deployment and hybrid efficiency.

Stella says McLaren have been forced into a reactive mode, running the car and only then discovering what the power unit is doing, rather than working from detailed predictive models.

“That’s not how you work in Formula 1,” he stressed, explaining that top teams normally simulate behaviour in advance, then refine performance against expectations. “Since we are a customer team, this is the first time that we feel we are on the back foot even when it comes to the ability to predict how the car will behave.”

Analysis of GPS and data overlays against Mercedes and other rivals has convinced McLaren that more performance is locked inside the power unit than they are currently able to access. Stella describes “low hanging fruit” that could be unlocked through closer collaboration with Mercedes engineers, but concedes it may not be enough to erase the gap to the works outfit.

He also hinted at structural limits to what a customer can influence, raising the possibility that some deployment strategies or control systems may be reserved, in practice if not in regulation, for the factory team.

Mercedes boss Toto Wolff, asked about customer unease, defended his company’s approach, arguing that with new rules and steep development curves, an engine supplier “cannot make everybody happy” but is focused on providing a “good service”.

For McLaren, the immediate task is twofold: recover from the bruising Australian weekend and accelerate their understanding of the Mercedes unit before the field regroups in Shanghai for the first Sprint event of the year. Stella insists Piastri, rattled but uninjured, will return sharper, and that McLaren will push hard to ensure they are no longer learning about their own engine only once the car hits the track.