Thomas Tuchel says he is still "sad" that Borussia Dortmund lost Mats Hummels, Ilkay Gundogan and Henrikh Mhkitaryan last summer.
Following an impressive first season with Dortmund, Tuchel saw three key players leave the club last summer in Hummels, Gundogan and Mkhitaryan, who moved to Bayern Munich, Manchester City and Manchester United respectively.
Although Dortmund splashed out over €110 million on eight new players ahead of the season, they have so far been unable to fill the void their former stars left, with the club currently sitting sixth in the Bundesliga.
"Of course I'm sad, you can see how important Mats is for Bayern Munich. You can see the talent, they show it week after week," Tuchel told ESPN FC's Raphael Honigstein. "Of course, I'm sad."
Tuchel recalled the moment when Germany international Gundogan, who helped Julian Weigl grow into his holding midfield role at Dortmund, informed him about his decision to move on to City.
"We sat there with my wife," Tuchel said. "We did not try to convince him otherwise because he made a very hard decision and he made his decision. In the end, my wife said, 'You can't believe how sad my husband is. He will not show you right now, we wish you all the best.' And she was right, we wish him all the best. We're still in touch."
Mkhitaryan appeared to have a special bond with Tuchel, under whom the Armenia international had his best Bundesliga season.
Tuchel said that he is happy the midfielder is now performing well at United after his initial struggle to adopt to the Premier League.
"We're still in touch with Micky and when he scores like he scored [against Sunderland], when he assists like he does, it's what he deserves after a difficult start at United," Tuchel said. "I was blessed to train these players and you have to let go. I can totally be happy for them."