Shinji Kagawa has confessed he will find life at Bourussia Dortmund difficult once manager Jurgen Klopp leaves at the end of the season.
Kagawa returned to Dortmund and Klopp after two indifferent years at Manchester United in 2014. He left Germany for Old Trafford after winning two Bundesliga titles under Klopp.
Kagawa featured frequently in the final year of Sir Alex Ferguson's tenure at the club where they won the Premier League but was left on the sidelines as the team toiled under David Moyes.
Klopp brought Kagawa back to Dortmund as Louis van Gaal arrived, where he has scored five times in 30 appearances so far this season.
But after a challenging year where the 2013 Champions League finalists flirted with Bundesliga relegation, Klopp is stepping away from the club at the end of the season and will be replaced by Thomas Tuchel, who enjoyed great success at Mainz.
'A new boss is coming, that means it is difficult for me like it was in Manchester,' Kagawa said. 'But the most important thing is to trust each other and set the same goals, then go forward in the same direction and work together.
'We have to work hard before the season starts. That's the only thing we can do. We must have the same target and believe in him, I'll do my best.'
Dortmund are seventh in the Bundesliga, three points behind Augsburg, who are fifth, with two games remaining.