Cesc Fabregas' side made it six consecutive victories in all competitions, continuing an impressive debut Champions League campaign that has already included two wins from their opening three matches.
Lens briefly threatened through Florian Thauvin, but Como took control inside the opening 10 minutes when Anastasios Douvikas converted from close range after Maximo Perrone's header from a corner.
Douvikas doubled Como's advantage before the break, finishing Alex Valle's header across goal, while Nico Paz capped an excellent first-half display by firing home during a swift counter-attack.
Como showed no signs of slowing down after the interval. Lucas Da Cunha made it 4-0 within two minutes of the restart, sweeping Paz's perfectly weighted pass into the net.
Marc-Oliver Kempf headed home the fifth before Douvikas completed his hat-trick, once again benefiting from Paz's outstanding creativity.
Substitute Mattia Liberali added a seventh after driving into the penalty area, while Lens briefly restored some pride when Ruben Aguilar scored with a superb volley.
However, Como continued their relentless attacking display, with Martin Baturina making it eight before Matteo Papacccioli completed the rout in stoppage time.
The emphatic victory was a historic night for Como and a major statement of their ambitions in Europe. Lens, meanwhile, must quickly recover from a humiliating defeat ahead of Sunday's Ligue 1 meeting with Olympique de Marseille.