Chelsea delivered a European boost when Willian's well-timed right-footed volley on 77 minutes earned Frank Lampard his first Champions League points as Blues boss.
The former midfielder's tactical tweak saw Reece James and Marcos Alonso adopt wing-back roles while Cesar Azpilicueta, Fikayo Tomori and Kurt Zouma made up a back three that fooled Lille, who simply couldn't cope with the Blues' initial width and control when in possession.
Lille benefitted from Chelsea's poor zonal marking to draw level midway through the opening half, but Callum Hudson-Odoi injected life into the visitors from the left wing as the Blues picked up all three points with a 2-1 victory.