PSG had plenty of possession but few ideas how to manage possession into scoring chances in the first half at Signal Iduna Park.
The straighter and sharper was the home team Dortmund.
A precise long ball from centre-back Nico Schlotterbeck was followed by a well-timed deep run by Niclas Füllkrug.
Then the striker offered two actions of class: takedown with the right foot, shot with the left.
The 31-year-old was then able to celebrate his third Champions League goal of the season – and finally a 1-0 victory at home in the first of two semi-finals against PSG.
The Paris club finally got their act together on German soil, played at a higher tempo and also found ways to clear scoring chances.
A couple of centimeters from giving an equalizing goal.
In the 51st minute, star Kylian Mbappé hit the post and in the same minute, in the aftermath of Mbappé’s miss, Achraf Hakimi also hit the crossbar.
On Tuesday, the return match awaits at the Parc des Princes in Paris.