Borussia Dortmund were made to work in the first half before overcoming the resistance of third division club KFC Uerdingen to win 2-0 and move into the German Cup second round on Friday.
Captain Marco Reus broke the deadlock in the 49th minute a with a shot from five metres after the ball had also made contact with his arm, and Paco Alcacer doubled their lead with a fine 70th-minute free-kick from 22 metres.
Dortmund, last season`s Bundesliga runners-up who beat double winners Bayern Munich to win the German Super Cup this month, had struggled against the confident hosts, who fielded ex-Dortmund player and 2014 world champion Kevin Grosskreutz.
Uerdingen had several chances in an entertaining first half with Dortmund`s Marwin Hitz tipping a powerful shot over the bar and Franck Ebina firing wide with only the keeper to beat after he snatched the ball from Mats Hummels in the 37th.
Hummels almost made amends a minute later when he curled a left-foot shot just wide of the post and Alcacer had his share of opportunities before Reus fired home for the lead.
With no video replay in the German Cup, Reus` goal stood, although the player looked to have touched the ball with his upper arm to control Manuel Akanji`s cross. Alcacer then made it 2-0 with his superb free-kick to end any hope for Uerdingen.
Cup holders Bayern take on Energie Cottbus on Monday, with the Bundesliga season kicking off five days later.