Rungnarai Kiatmuu9 (Thai: รุ้งนารายณ์ เกียรติหมู่ 9), born Worawut Kotprakhon on May 17, 1995, in Prakhon Chai, Buriram Province, Thailand, is a professional Thai Muay Thai fighter. He is a former Lumpinee Stadium champion and Rajadamnern Stadium champion, and currently competes under ONE Championship.
Biography and Career
Rungnarai began training in Muay Thai at the age of 8 at a small local camp called Lukhokphet near his village. At age 14, he moved to the Kiatmoo9 gym in Tako Thapi to train full-time. He made his first fight in Bangkok at age 15 under the Kiatmoo9 banner.
He is known as a Muay Femur (technical) fighter, with a fighting style emphasizing technique and right-leg strikes. He has fought in the light flyweight, flyweight, super flyweight, and bantamweight divisions.
In July 2019, Rungnarai was initially awarded the 2018 Sports Writers Association of Thailand Fighter of the Year award. However, shortly after receiving the honor, he lost by knockout to Yothin FA Group. The association subsequently revoked the award and decided that no fighter was worthy of the title that year—a decision that was widely criticized within the Muay Thai community.
After a period away from competition during the COVID-19 pandemic, Rungnarai worked as a Muay Thai instructor at Evolve MMA in Singapore. He returned to competition in ONE Championship in October 2024, where he lost by disqualification after landing an illegal kick on a downed opponent, Mikel Fernández. He returned to winning form in May 2026 with a unanimous decision victory over Den Sitnayoktaweeptaphong at ONE Friday Fights 154.
Titles and Accomplishments
- 2013 – Thailand Light Flyweight (108 lbs) Champion (Professional Boxing Association of Thailand)
- 2016 – Rajadamnern Stadium Light Flyweight (108 lbs) Champion
- 2017 – True4U Flyweight (112 lbs) Champion
- 2018 – Lumpinee Stadium Super Flyweight (115 lbs) Champion (one successful defense in 2019)
- 2019 – True4U Bantamweight (118 lbs) Champion
- 2018 – Sports Writers Association of Thailand Fighter of the Year (subsequently revoked)
Fighting Style and Record
Rungnarai is classified as a Muay Femur (technical) fighter, known for his right roundhouse kick and right knee strikes. As of his most recent records, he has compiled approximately 119 wins (20 by knockout), 34 losses, and 5 draws across a career spanning over 150 professional fights. He stands 166 cm (5 ft 5 in) and fights from an orthodox stance.
