Dortmund needed an own goal from Cologne defender Marvin Matip, five minutes following Zidan's introduction, to claim all three points.

Egyptian international Zidan started on the bench as Dortmund coach Jurgen Klopp preferred to field Nelson Valdez and new signing Lucas Barrios upfront.

The in-form striker replaced Paraguayan Valdez 20 minutes from time and was instrumental in helping the hosts create some goalscoring opportunities.

Zidan's energetic efforts unsettled Cologne's defense. He also had two decent shots blocked by the keeper.

Elsewhere, Gamal Hamza's Mainz, one of the Bundesliga newcomers, held Bayer Leverkusen to a 2-2 draw.

Egyptian forward Hamza, who joined the club in the close season after his contract with Zamalek expired, was left out of the match's squad.

Under-19 coach Thomas Tuchel led Mainz after they parted company with Jorn Andersen last week.

Dortmund match highlights