Japan international Shinji Kagawa sparkled on his return to Borussia Dortmund, scoring one goal for the Ruhr Valley club and helping set up another in a 3-1 win over Freiburg.
Elsewhere, champions Bayern Munich beat VfB Stuttgart 2-0, with Frenchman Franck Ribery scoring on his season debut as they prepare for their Champions League match against Manchester City next week.
The 25-year-old Kagawa, who had spent two seasons at Manchester United after winning consecutive Bundesliga titles in 2011 and 2012 with Dortmund, was welcomed back with roaring applause and he instantly rewarded the fans.
First he set up Kevin Grosskreutz, whose cutback found Adrian Ramos for the lead.
Dubbed the 'Lost son' by German media, the attacking midfielder fired in from 12 metres in the 41st minute as hundreds of Japanese flags were unfurled in the stands.
Substitute Pierre-Emerick Aubameyang completed Dortmund's successful dress rehearsal for their Champions League group opener against Arsenal next week, with a scintillating 50-metre sprint and a superb chip for their of the afternoon in the 78th.
Freiburg scored a late consolation goal with Oliver Sorg.
Dortmund have six points from three games, one behind Bayern who never hit top form against Stuttgart.
The Bavarians, missing several players through injury, were rarely threatened and Mario Goetze made the most of a bad Stuttgart clearance to fire in for the lead in the 27th minute.
France's Ribery, who missed the World Cup with a back injury, came on for Goetze in the 68th and doubled their lead with a low shot from a tight angle five minutes before the break.
Bayern München 2 - 0 VfB Stuttgart
Borussia Dortmund 3 - 1 SC Freiburg
Hertha BSC 1 - 3 Mainz 05
Hoffenheim 1 - 1 Wolfsburg
Paderborn 0 - 0 KölnKöln