[4] Ramazanov made his ONE debut at ONE Championship: Kingdom of Heroes on October 6, 2018 against the heavily favored Phetmorakot Petchyindee Academy.
[5] Despite receiving a cut on the back of his head, Ramazanov outstruck Phetmorakot and fought on to claim the unanimous decision victory.
Only two weeks later, Ramazanov stepped in on short notice to face Saemapetch Fairtex at ONE Championship: Conquest of Champions on November 23, 2018.
[17][18] Despite having mostly fought under Muay Thai rules and showing signs of slowing down in the later rounds, Alaverdi Ramazanov was able to adapt and scored a crucial knockdown before winning the fight by unanimous decision, becoming the first ONE Bantamweight Kickboxing World Champion.
[24] Ramazanov is scheduled to return against former ONE Featherweight Muay Thai title challenger Pongsiri P.K.Saenchaimuaythaigym at ONE Championship: NextGen III on November 26, 2021.
[27] Ramazanov was scheduled to face Nong-O Gaiyanghadao for the ONE Bantamweight Muay Thai World Championship on January 14, 2023, at ONE Fight Night 6.
[34] Ramazanov was issued a six-month suspension from ONE Championship, along with his coach Mehdi Zatout, due to his altercation with the two-sport World Champion Jonathan Haggerty at ONE Fight Night 16 on November 4, 2023 in Bangkok, Thailand.