The Germany international has been linked with a move to Anfield ever since the arrival of Jurgen Klopp.
“I have rarely seen a man who can motivate you with his speeches, this quality makes him unique,” Gündoğan was was quoted as saying by Sport1.
Dortmund rejected an approach from United just before the end of the summer window for Gündoğan according to the German newspaper Express.
Klopp won two Bundesliga titles and finished the 2012-13 Champions League as runners-up during his time in charge of Dortmund.
Gündoğan has started the season well in the Bundesliga under Dortmund’s new manager Thomas Tuchel. Dortmund sit in second place in the Bundesliga with 20 points in nine games.
Liverpool currently sit in ninth place in the Premier League with 14 points in ten games.