Jürgen Klopp has admitted that he failed in an attempt to re-sign Shinji Kagawa from Manchester United, having only sold the Japanese international last summer.
Kagawa was signed by former United boss Sir Alex Ferguson for £17m ahead of last season, but he endured a disappointing campaign that was hit by injury despite the club triumphing in the Premier League.
And Klopp, who led his side to the Champions League final only to lose to rivals Bayern Munich, has admitted he spoke to Kagawa about a potential return to Germany only to be knocked back immediately.
"It was clear relatively quickly, Shinji wants to prevail this year at Manchester United," Klopp said. "I did not expect a different answer, you just have to ask even once."
Kagawa appeared on Japanese football show ‘Foot Brain’ during United's pre-season stop-off in his homeland, with the attacking midfielder claiming that he would like to play again for his former club some day if they were to have him back.
Kagawa said: “Someday I want to return to that team (Dortmund), I will be back someday…if Dortmund is okay with it.”
This admission came after he had reflected on his season, suggesting despite the obvious success, he was not entirely happy with how it went from a personal point of view.
“It was a tough time for me with a lot going on in my head," Kagawa said. "I am not happy with my performance for the team at all. I didn’t score that much and I also had my (knee) injury.
“Despite that, it was great we won the league, I just don’t feel that I achieved everything that I wanted. For me personally, it wasn’t a good season.”
Kagawa spoke about his future, but he insists that he doesn't regret the decision to leave Dortmund having seen them go on to reach the Champions League final.
"I was proud to see my former team play in the Champions League final, and I was very excited for them," he said.
"But it didn't make me feel I had made the wrong choice.
"In fact it made me feel stronger because I want to be on the same field in future."