Mercedes turned up at Silverstone with a qualifying weapon nobody else had spotted, and it came down to something that looks like a mistake: George Russell and Kimi Antonelli briefly lifting off the throttle a few metres before the timing line. The gain was tiny, the legality has since been confirmed, and the downside of getting it wrong is a disqualification.
The technique lives in the small print of F1's 2026 energy rules. On the approach to the line, deployed electrical power is not allowed to drop by more than 50kW per second, the so-called ramp-down rate, which normally bleeds the MGU-K's 350kW away before a car crosses the line. Mercedes found that the regulations waive that requirement when a driver comes fully off the throttle. Lift before the battery empties and the MGU-K can cut its output instantly while staying compliant, keeping full deployment alive for longer on the dash to the line. The Race put the benefit at around 0.05 seconds a lap. Telemetry published by gpblog showed Antonelli's throttle at 40% where Hamilton's stayed at 94%, the Mercedes carrying less speed through that final phase but more energy in hand.
Antonelli described a method that runs against instinct. "It wasn't easy. In Q3 I also had to lift off, and with these power units it's always a bit complicated because sometimes you have to drive in a way that doesn't feel completely natural," he said. The payoff arrives later on the straight. "You might lose a little on corner exit, but then you make it back because by delaying the moment you get back on the throttle, you have more energy available further down the straight." Mercedes drilled it in the simulator and fed the drivers an audio tone when the battery reached a set level, so they knew the exact instant to lift. "It's complicated, but thanks to the preparation we did together with the team, it all became almost second nature," Antonelli said.
FIA sources confirmed to The Race that the tactic was fully within the rules, provided the power never fell by more than 50kW in a second before the throttle lift.
It still caught the paddock's fastest team off guard. "When we first noticed it yesterday in sprint qualifying, as Antonelli was doing it, it caught us a little by surprise because it's not something we'd discussed," said McLaren team principal Andrea Stella. Oscar Piastri was blunter: "I didn't even know they did it, which probably says a lot."
Copying it is not a simple software swap. "I'm not sure at all that it's available to us, because it requires probably some further elements to use the power unit, let's say," Stella said, noting that McLaren only expects the latest Mercedes power-unit specification from the Belgian Grand Prix onward.
The reason rivals have not rushed to bolt it on is the risk. Lift a fraction too late, let the battery hit zero, and the MGU-K cuts power under load, breaching the technical rules and inviting exclusion from qualifying and a start from the back of the grid. Battery levels vary lap to lap, so there is no fixed braking marker to lean on, only the tone in the driver's ear. The Race framed copying it as a genuinely high-stakes call: a few hundredths on the line weighed against the risk of throwing away a Saturday.
For now it is a neat illustration of where the 2026 rules are steering the sport, with lap time buried in the fine print and found first by the team quickest to read it. Whether Red Bull, Ferrari and McLaren follow at Spa, where the run to the line is longer and the sums change, is the next question.
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