Shinji Kagawa believes the immediate impact made by Jurgen Klopp at Liverpool proves his greatness as a manager.
The 26-year-old spent two seasons under the German at Borussia Dortmund, having been signed by him from Cerezo Osaka before moving to Manchester United in 2012.
Kagawa returned to spend a final year under Klopp in 2014 at Dortmund – now managed by Thomas Tuchel – and he has been impressed from afar with his former boss' early work at Anfield after replacing Brendan Rodgers.
"I am interested in how much and how quickly Klopp, the manager that I know, can change the team at Liverpool," the Japan international told Omnisport.
"He is a great coach and the results prove it, so I hope it will continue for him and I am interested in how much they can contend as a team this season.
"Already they drastically changed now and I have read articles that they won eight games in the last 10 games [seven in 11]. I do watch the games sometimes when I have time or when they broadcast on TV."
Kagawa discussed the close bond he shared with Klopp while at Dortmund and detailed the pair's emotional farewell after his switch to Old Trafford was secured.
The attacking midfielder continued: "I remember him expressing his emotions out all the time, his goal celebrations, encouraging the team, attitudes to communicate and give love to each player.
"Every moment with him is a good memory for me rather than picking a particular one up. It is also good memory to win the titles with him.
"He trusted and featured me. I was not famous coming from the second division of the J.League, so I totally appreciate that. It is great memories with him, the goal in the derby match, the game I scored to seal the title and the celebrations.
"The trust between us got bigger and bigger and then I could play in his team again. [The farewell] is a bit exaggerated, but I went see him to say thank you for the two years, in the last moment as my move was almost decided.
"When I went see him and did the last greetings, the tears naturally came out. He helped me to build up the steps leading to Manchester United, the club that everyone all over the world knows, the club that I have known since a little kid, in only two years after I joined from Cerezo.
"Showing my further development and better performance is the repayment to him from me. My career still goes on and I do not want to be remembered as I was good only during that period. And now I have got the new manager, so I want to achieve good results."
