McLaren's Lando Norris has become the final Mercedes-powered driver to take a new power unit and will start at the back of the Mexico City Grand Prix grid.
McLaren's decision to fit a new system in Norris' MCL35M comes following lengthy discussions with Mercedes and following a troubling practice for the Woking-based team as it was off the pace.
Norris has taken a new internal combustion engine, turbocharger and MGU-H.
It means all eight drivers this season in Mercedes-powered cars have taken a new system and been hit with power unit penalties.
Norris now joins Aston Martin's Lance Stroll and Yuki Tsunoda in his AlphaTauri at the rear of the field for the start of Sunday's race at the Autodromo Hermanos Rodriguez.
Alpine's Esteban Ocon will join the trio at the back as the Frenchman has taken a new PU, with all components.
Their positions on the final four grid slots will be determined by their performance in qualifying so there is at least incentive to perform across the hour-long session.
With McLaren so far struggling at the high-altitude circuit, and with Norris towards the rear, it now appears likely the team will lose its third place in the constructors' table as it holds only a three-and-a-half point lead over Ferrari.