South Korean challenger Chi In-jin reclaimed the WBC featherweight title with a unanimous decision over Rudy Lopez in Seoul on Sunday.
The Mexican was defending his title for the first time.
Chi, rated No 3 by the WBC and known for his strong chin and brawling style, repeatedly fought his way off the ropes to take the bout 117-111, 116-112 and 116-113, extending his record to 31-3-1, with 18 knockouts.
The South Korean's single-minded attacks saw him up the tempo despite injuring the second finger in his left hand in the eighth. Local officials said it appeared broken, and Chi was taken to a nearby hospital after the fight.
Lopez (19-3-1, 13 KOs), who looked unsteady in the final rounds, said his opponent's strength was his chief asset and this ultimately decided the bout.
"He's a very strong fighter but he has no technique," Lopez said with the help of a translator.
Chi, who at 33 is 10 years older than Lopez, had shed 11 kg for the fight to weigh in at exactly 57 kg.
Chi gave up the WBC title to Takashi Koshimoto of Japan in January after holding it for almost two years. Koshimoto then lost it to Lopez in July, also on his first defence, before retiring.