Japan's Yudai Shigeoka relinquished his WBC minimumweight championship to Filipino challenger Melvin Jerusalem in a split-decision upset on Sunday.
Younger brother Ginjiro Shigeoka defended his IBF minimumweight crown with a second-round knockout of Jake Amparo of the Philippines earlier in the world championship doubleheader at Nagoya Congress Center.
Former WBO champion Jerusalem scored knockdowns in the third and sixth rounds on his way to finishing ahead on two of the three judges' scorecards at the end of 12 rounds.
Having fallen behind early, the 26-year-old Yudai worked his way back into the bout with some solid combinations but was unable to put sixth-ranked challenger Jerusalem on the canvas.
The Japanese southpaw's record now stands at eight wins and one loss, with five wins by knockout, while Jerusalem improved to 22-3 with 12 KOs.
The 24-year-old Ginjiro (11-0, 9 KOs) completed his second title defense with a body-shot knockout of Amparo (14-6, 3 KOs), who stepped in at short notice after countryman ArAr Andales pulled out of the bout for medical reasons.
The younger Shigeoka ended the contest at 1:15 in the second with a left to the sixth-ranked challenger's midsection.
"I didn't expect a body-shot knockout," he said. "I'm relieved. I could sense how dangerous he was as an opponent."
Fighting on the same card, Tomoki Kameda (41-4, 23 KOs), the last of the three Kameda brothers still active in the ring, won his non-title fight against Mexican Kevin Villanueva (22-5, 15 KOs), whose corner threw in the towel between the fifth and sixth rounds.
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