Kim, a former South Korea coach, was with the Indian shuttler when she thrashed 2017 champion Okuhara 21-7 21-7 in one of the most lop-sided finals in the history of the tournament.
"Perfect execution! I was so happy (with) how she played!" Kim was quoted as saying by the Badminton World Federation (BWF).
"I mean, yeah! That's the way I play when I play against her. I feel over the moon because we did it!" Kim, who changed her name to Ji Hyun Marr, but is better known worldwide by her maiden name, was handed the responsibility to sharpen the skills of former world No.2 Sindhu with the World Championships and Olympics in mind.
"I got the job offer and I decided to go. Five months later, we've got a world champion in Sindhu!," said Kim, who was among the coaches sacked last September by the Badminton Korea Association for the national team's failure to win medals at the Jakarta Asian Games.
"She had more individual training. We worked on her net skills and deception for hours. Everyone knows she's a great player but she was doing the same things over and over in matches," added Kim.
Meanwhile, Sindhu, who had undergone rigorous training under the South Korean coach, also showered praise on Kim and said they both share a good communication.
"It has been good. I am happy with my performance. With Kim, I have a good communication," Sindhu said.
"She pointed out a few mistakes that I was doing at the net, and overall, so I had to improve on that aspect. Her mindset and thinking is different and she motivates me a lot. Every coach has a different approach and I got used to her quickly. She joined after All England, so it took some time to get used to her way. Now we understand each other well," she added.
( With inputs from IANS )