The new-for-2019 power unit, Mercedes-AMG F1 M10 EQ Power+, was said to be less powerful than Ferrari's (the Ferrari 064) - specifically in terms of outright qualifying power modes, straight line speed, and electrical power development. Despite this, it was still considered the most fuel-efficient power unit in the field, There were, however, some reliability concerns when the third iteration of the engine (Phase 3) experienced significant failures in the 2019 Belgian and Italian Grands Prix.