PV Sindhu created history by becoming the first Indian to win the BWF World Championship title, by defeating Japan’s Nozomi Okuhara. 

Post her win, she revealed to reporters that she has her new coach to thank for this victory. 

I really focused this time and of course now I have a new coach — Miss Kim. I’ve been training under her for the past couple of months and certainly I have improved a lot under her. I am really very thankful to her. 
BWF Badminton News

Sindhu’s coach Kim Ji-hyun is a former badminton player, who has participated in 2 Summer Olympics and won the women’s singles title at the National Championships tournament in 1997 and 1998. She has over 20 years of experience in coaching. Kim was brought in to diagnose problems and find solutions for Sindhu after she had a roller-coaster of a season. Talking about Sindhu, she says

Sindhu’s powerful and has a good physique, but I feel she has to develop more skills.. Step by step. We’re working on skills, and changing tactics, as you can’t use the same tactics over and over again.
Outlook India

The BWF win has a brought in a much needed triumph in what has otherwise been a lacklustre year for Sindhu. She said that while this is a very special moment, she is not looking too far ahead with the 2020 Tokyo Olympics just under a year away.