Mercedes delays ADUO engine upgrade to October, forcing Antonelli to start from the back at Monza

Kimi Antonelli will start from the back of the grid at his home Italian Grand Prix at Monza after Mercedes confirmed the new power unit he takes on this weekend will not feature the upgrade the team is permitted to introduce under Formula 1’s Additional Development and Upgrade Opportunities scheme.

Mercedes has been granted one ADUO token to introduce an updated power unit, but the team has chosen to save that upgrade for the American leg of the 2026 calendar — either Austin or Mexico City in October. The unit Antonelli uses at Monza will therefore be a straight replacement rather than an improved one.

The championship leader has already used four internal combustion engines this season, and the addition of a fifth exceeds his allowance, triggering the mandatory grid drop. Mercedes opted for Monza specifically because it is considered one of the easiest circuits on the calendar for recovering positions from the back.

Reliability issues and component failures have depleted the pool of engines available to Antonelli, making the introduction of a new unit at this stage unavoidable. Team-mate George Russell finds himself in a marginally better position: he has used the same number of components overall but retains a larger pool, having suffered fewer terminal failures.

Both Antonelli and Russell are expected to use six power units across the full 2026 season, meaning further grid penalties are likely before the year is out. With 11 rounds still remaining on the calendar — subject to the status of the Qatar and Abu Dhabi races — teams are actively mapping out which circuits would best absorb the impact of additional penalties.

The decision to introduce a fresh but unupgraded engine now, rather than waiting for the ADUO unit, underlines the extent to which reliability concerns have shaped Mercedes’ strategy. The team’s upgraded power unit, when it does arrive in October, will be shared by both drivers and represents one of the few remaining opportunities to close any performance gap in the second half of the season.