It was the primary time Dortmund have misplaced to Freiburg in Germany’s high flight for 11 years, with Saturday’s setback coming simply 4 days after shedding 3-1 to Bayern Munich within the German Super Cup.
“We made stupid mistakes, twice!” grumbled Dortmund centre-back Manuel Akanji.
“We gave away a free-kick for the primary and the second aim was a counter assault.
“We can’t invite opponents to score, especially when we have Champions League aspirations.”
Dortmund will uncover their group opponents when the draw for the Champions League is made on Thursday.
Freiburg raced into the lead when dead-ball skilled Vincenzo Grifo blasted in an outstanding free-kick after simply six minutes.
Dortmund thrashed Eintracht Frankfurt 5-2 final Saturday on the opening weekend, however the guests’ defensive frailties emerged once more having been an issue final season.
After England midfielder Jude Bellingham misplaced the ball, Freiburg ahead Roland Sallai was left unmarked to smash home his shot because the hosts doubled their lead on 53 minutes.
Bellingham made amends by pressuring the defence with a powerful run which prompted Freiburg midfielder Yannik Keitel to place the ball into his personal web with half an hour to go.
Freiburg had been winless of their earlier 19 conferences with Dortmund relationship again to May 2010.
Bayer Leverkusen later romped to a 4-Zero victory at home to Borussia Moenchengladbach.
Visiting goalkeeper Yann Sommer had a nightmare begin when Mitchel Bakker’s shot hit the publish, deflected off the Gladbach keeper and rolled over the road for an personal aim.
Czech striker Patrik Schick then doubled Leverkusen’s lead on eight minutes.
Gladbach misplaced striker Marcus Thuram with an harm after simply 20 minutes, then their captain Lars Stindl had a penalty saved simply earlier than the break.