By Lerpong Amsa-ngiam
The world No 15 committed a series of unforced errors and all her shots were repelled by the 1.55cm-tall opponent, who wrapped up the second-round encounter 21-10 17-21 21-16 in 62 minutes.
“I really thank God for inspiring me to play so well today. I’m so happy to win the match as she is the defending champion,” said the 20-year-old from West Java, ranked only 33rd in the world and still seeking her maiden Super World Tour level title.
“I tried to be patient and play safe. Nitchaon has powerful shots so my plan was to stay in the rallies and hit everything back. It’s very hard to get the better of her.
“I was a bit surprised I could beat her. From now on I will take one match at a time and hope I can win the tournament.”
Fitriani will next play 2018 Vietnam Open winner Yeo Jia Min of Singapore, who beat Yvonne Li of Germany 21-16 21-18.
Nitchaon was on the verge of tears in her post-match interview and admitted she had been far from her best.
“She was so solid and I ended up making mistakes,” she admitted. “I only have myself to blame. The organisers changed the shuttlecocks today and I just couldn’t hit it at all.”
However 2017 champion Busanan Ongbamrungphan was the first Thai singles player to reach the quarter-final this year after she beat Ruselli Hartawan of Indonesia 21-14 21-9.
Thailand is now without any players in the men’s singles following the defeats of national champion Sitthikom Thammasin and his ex-World Junior Championship teammate Pannawit Thongnuam in the second round.
A day after dethroning the Kingdom’s No 1 player Kantaphon Wangcharoen, Sitthikom was nowhere near his best and was overshadowed by Firman Abdul Kholik of Indonesia 16-21 20-22.
Pannawit, after showing some stunning shots in the first game, faded badly in the decisive game and lost to Cheam June Wei of Malaysia 21-14 17-21 16-21.
Thailand’s top three players, including Khosit Phetpradab and Suppanyu Avihingsanon, have now all been knocked out since the first round on Wednesday.
Top seed Lin Dan of China was put to the test by Lee Cheuk Yiu of Hong Kong before advancing by the skin of his teeth 21-19 15-21 22-20. Eighth seed Lu Guangzu of China also advanced, beating Koki Watanabe of Japan 23-21 21-17.
In the mixed doubles, sixth seeds Savitree Amitrapai and Nipitphon Phuangphuapet beat Venkat Guarav Prasad and Juhi Dewangan of India 21-16 21-17 to set up an all-Thai affair with Parinyawat Thongnuam and Kittipak Dubthuk, 21-12 21-12 winners over Yang Ming-Tse and Wu Ti Jung of Taiwan.