The ONE 166 tournament was held in Lusail (Qatar), where the main event was the fight between Anatoly Malykhin and Reinier De Ridder, a match for the organization's middleweight championship belt. Last June, Anatoly finished off Arzhan Bular and became a double champion of the promotion. Malykhin now won a third title in the third division, setting a unique achievement. De Ridder was defeated by TKO in the third round.

With the win, Malykhin increased his record to 14-0 in MMA and became the first three-time champion in ONE history. He recorded a second consecutive knockout victory over De Ridder to claim his second belt. Reinier was a two-time champion, but in 2022 Malikhin took the light heavyweight title from him. De Ridder now has a record of 16-2 in MMA.