The Belgian has returned to Stamford Bridge for a club-record £97 million ($132 million) as the missing piece of a proven goalscorer to turn the Champions League winners into English champions.
Thomas Tuchel’s men have made a formidable start towards that aim with six points, five goals scored and none conceded from their opening two games of the Premier League season.
Arsenal, by contrast, have yet to register a point or score a goal as the gulf between Mikel Arteta’s men and the title contenders was exposed.
Circumstances have also gone against Arteta as he lost £50 million signing Ben White before the game to the fifth positive case for coronavirus among his squad in the past 10 days.
A difficult start could get even worse with a trip to defending champions Manchester City next weekend before an international break.
Arsenal’s latest signings Martin Odegaard and Aaron Ramsdale were not registered in time to feature.
Those arrivals took the Gunners spending in the transfer window above any other Premier League club despite a fifth season without Champions League football.
But whereas Chelsea needed to fill just one position to complete a squad already stacked with quality, Arsenal appear to be starting from scratch.