Brendan Rodgers was keen to lure the Armenia international to Anfield back in 2013, but Klopp convinced him to sign for Borussia Dortmund instead.
Mkhitaryan eventually left Dortmund for United during the close-season, but he could have been lining up for Liverpool in Sunday's clash at Old Trafford had Klopp not interfered.
"I spoke two or three times on the phone to Rodgers, he was saying he really wanted me and that I would get to play with Luis Suarez and Steven Gerrard," Mkhitaryan told the Daily Mail.
"Half of me thought I had to go there, the other half was not so confident, that the gap to the Premier League might be too big for a skinny player from the Ukrainian League.
"Two weeks later, Klopp broke off his holiday on an island next to Denmark to come and see me in Dortmund. I knew he had a good reputation for working with younger players and, after we met, I felt more comfortable to sign for Dortmund. I think I made the right decision."
Mkhitaryan will be taking on his former boss on Sunday and he has nothing but good memories of his time with the German.
"He was always next to you if there were playing problems or life problems. He is a good person," he added.
"In particular, he helped me a lot because I was thinking too much about football. I took defeats too seriously, I would obsess about any chances I missed. He told me that it is just life and I had to let it go because when the next chance comes, I needed to be in the right frame of mind to take it.
"I learned to realise that everyone makes mistakes in life and you cannot worry on the pitch. You have to forget about it."