Dortmund host the Premier League outfit in the first leg of their Europa League quarter-final on Thursday as the coach returns to face the team he led to Bundesliga glory twice and a Champions League final.
And Sahin insists the pristine relationship between Klopp and the German team will not be tarnished regardless of how their European encounter turns out.
"We have worked together for seven, eight years," Sahin told Sport1.
"That he knows us is beyond question. We know him well. We all have a great relationship with Klopp. That will not suffer in these two games."
READ MORE | Gundogan back in training ahead of Liverpool clash
Sahin was on loan at Anfield from Real Madrid in 2012-13 before returning to Dortmund, and despite his short and unsuccessful spell in England he had no complaints about the club.
"I was only there for three and a half, four months," he added.
"It was a short but very nice time. I cannot say anything bad about this club. It was my desire to go back to Borussia.
"What I will never forget is the training ground. The club Liverpool is great.
"Even if they have not won a major title since 2005, it is an extremely well-organised team."