What happened: George Russell will race Mercedes' older-specification car at the Singapore Grand Prix, while Kimi Antonelli will run the team's upgraded package. The split strategy comes as the constructor attempts to understand why its Malaysia updates underperformed.

Why it matters: The specification test adds a critical variable to the intra-team dynamic. Russell is already facing a back-of-the-grid penalty in Singapore due to an unavoidable engine change following his retirement at Sepang. Data gathered from Antonelli's car will determine the development direction for the final stretch of the schedule.

What to watch: Practice sessions at the Marina Bay Street Circuit will provide the first direct performance comparison between the two packages.