The former Spurs player and coach was very impressed with the German side.
A brace from Marco Reus after Pierre-Emerick Aubameyang had given Dortmund the lead proved enough for the German side in a dominant display.
Clive Allen played at Spurs for four years and also acted as caretaker manager on two occasions for the club.
He was working for the BBC covering the game and immediately after Spurs had left the field of play Allen had this to say about the performance:
"It could well have been five.
"Dortmund did not disappoint - some of their football was fantastic to watch, and their third goal was one of the best you will see this season."
Whilst many were picking up on the fact Mauricio Pochettino had decided to rotate his team for this big game Allen instead decided to revel in the brilliance of the Bundesliga side.
Dortmund were incredible throughout the game and the passing and movement was too hot to handle for Spurs. Whether Spurs' strongest team would have fared any better is up for debate.
The third goal was magnificent, coming after 21 passes, with Reus tucking away on the half-volley.
Tottenham now face an uphill battle to make it through to the next round of the Europa League.