Portugal international Guerreiro struck in each half to help the Bundesliga leader dispose of its hapless host and leapfrog Atleti, held to a goalless draw against Club Brugge, thanks to a superior head-to-head record.
Dortmund's largely straightforward win was achieved despite Lucien Favre resting nine members of the team that triumphed 2-1 over Revierderby rival Schalke on the weekend.
Chances were scant after Dortmund went ahead in the 15th minute, but top spot and a fifth clean sheet in six Champions League engagements made for a successful trip to the principality.
