Japanese boxer Kazuki Anaguchi died Friday from injuries he sustained in a Dec. 26 fight in Tokyo, the Japan Boxing Commission announced.

The 23-year-old Anaguchi (6-1, 2 knockouts), a bantamweight who turned pro in 2021, suffered a subdural hematoma during his fight with Seiya Tsutsumi, which was broadcast on ESPN+ as part of the Naoya Inoue vs. Marlon Tapales undisputed junior featherweight title fight.

Anaguchi was dropped four times in the fight but lasted the distance, losing the Japanese bantamweight title fight by unanimous decision.

According to the WBC, Anaguchi’s legs began twitching in the corner, and he was taken to the hospital afterwards where he underwent emergency brain surgery. He never regained consciousness.

Anaguchi had excelled as an amateur, representing Japan at the 2015 AIBA World Junior Championships in Russia. He had moved quickly as a professional, having turned pro in six round bouts and defeating former title challenger Jonathan Taconing in just his fourth bout.