Two first half goals by Coys skipper Cristian Romero and striker Dominic Solanke were enough to see off a lacklustre BVB side who had to play most of the match with ten men following a Daniel Svensson red card.
Spurs took the lead in the 14th minute after Wilson Odobert missed a volley but regained possession to put in a pin point low cross for Romero to finish from close range.
The situation went from bad to worse for Dortmund ten minutes later after Daniel Svensson caught Odobert with a studs up challenge that led to his sending off following a VAR check.
The home side doubled their lead in the 37th minute thanks to another Odobert assist soon after with England international Solanke tapping in with a clever flick to give Spurs a 2-0 lead heading into half time.
Tottenham seemed to be content with the result in the second half, barely threatening the opposition goalkeeper with the visitors coming closest through a Nico Schlotterbeck late header that was tipped over by Guglielmo Vicario.
Germany defender Schlotterbeck revealed his disappointment with the BVB's overall performance against the Premier League side.
"We didn't quite find a way to play the game we wanted to play," said the centre back.
"Tottenham weren't any better than we expected. The first five minutes were okay. After that, we allowed them too many set pieces, defended poorly and then got into a rut that saw us lose every ball.
"We got a bit stuck in the first half. The red card was just very bitter. In the second half, we put in a decent performance – considering we were a man down. If we had pulled a goal back, it might have got exciting again. But as it was, we deserved to lose."
Meanwhile goalscorer Dominic Solanke feels the result can help motivate the team following indifferent results domestically.
"We've done quite well in the Champions League, said Solanke to TNT Sports after the match.
"And if you look back to last season and how well we did in the Europa League, it definitely gave the team confidence.
"We know we haven't been good enough in Premier League this year so hopefully this gives us the extra boost, we can improve in the league and continue in the Champions League."
The result sees Spurs temporarily move into fourth spot on the League Phase table with one round of fixtures still to play, where they are set to face Eintracht Frankfurt in Germany.
Meanwhile, Dortmund are sitting in 12th spot on the table and will host inter in their last match of the League Phase.
