Flyweights Antonio Cesar and Viet Anh Do will meet over three rounds on Dec. 18 at ONE Fight Night 50 at Lumpinee Stadium in Bangkok, Thailand, in a bout expected to determine the next challenger for the ONE flyweight title in 2027. Cesar (15-2) arrives on a 10-fight winning streak and is 4-0 in 2026, while Do (7-0) has stopped his last three opponents and carries a 100 percent knockout rate in ONE. The flyweight belt is currently held by Avazbek Kholmirzaev.
Flyweights Antonio Cesar and Viet Anh Do will meet in a three-round bout on Dec. 18 at ONE Fight Night 50, as first reported by MMA Fighting. The card takes place at Lumpinee Stadium in Bangkok, Thailand, and the winner is expected to emerge as the next challenger for the ONE flyweight title in 2027.
Cesar brings a 15-2 record into the matchup and the longest active run of the two. He has won 10 fights in a row and is a perfect 4-0 in 2026, a busy year that has put him firmly in the title conversation. A 10-fight streak means his last defeat came well before this year, and he has not dropped a decision or a finish since.
Do is unbeaten at 7-0 and has finished his last three opponents. He carries a 100 percent knockout rate in ONE, meaning every win he has recorded in the promotion has come by knockout. That gives the matchup a clear stylistic contrast on paper: Cesar's volume of recent wins against Do's proven finishing power.
The experience gap is notable. Cesar has 17 professional fights to Do's seven, a difference of 10 bouts, and he has already fought four times this calendar year. Do is working his way up the ladder with a shorter résumé but no blemish on it.
The flyweight belt is currently held by Avazbek Kholmirzaev, who will be watching a contender emerge from this fight.
Why it matters
- The winner is expected to earn a shot at Kholmirzaev's flyweight title in 2027.
- Cesar's 10-fight streak meets Do's unbeaten record, so one run ends on Dec. 18.
- Do's 100 percent knockout rate in ONE faces a veteran who has stayed active and undefeated through 2026.
The bout is scheduled for three rounds rather than five, which means neither fighter will have the cushion of a championship distance to work back from a slow start. For Do, the fight is a first major test of his record against an opponent with more than twice his number of professional bouts. For Cesar, it is a chance to turn a year of consistent wins into a title opportunity.
