Borussia Dortmund boss Jurgen Klopp says Shinji Kagawa is returning to his best.

After two difficult years at Manchester United, the Japan midfielder was sold back to BVB last summer.

"Shinji is a player who moves extremely well in the most difficult parts of the field, between the two lines of four players," Klopp told the UEFA website.

"It's like he's the sauce in a sandwich, because players arrive there from all sides."

Kagawa is back with BVB after a month away in Australia with the Asian Cup.