Lewandowski netted for the sixth successive Champions League game when he opened the scoring from the spot.
And the prolific forward soon doubled Bayern’s lead by firing past Georgiy Bushchan from Thomas Muller’s pass.
Serge Gnabry thumped in a third before Leroy Sane and Eric Maxim Choupo-Moting wrapped it up.
Bayern have now scored eight goals in their opening two Group E games.
They sit top with maximum points and visit Benfica, currently second on four points, in their next European game.