Melvin Jerusalem lost via unanimous decision to Wanheng Menayothin in their world minimumweight title fight in Wanheng's home country of Thailand.
Two judges scored it 114-113 in favor of the reigning world champion and a third judge had it 115-113.
It was the first loss in 12 fights for Jerusalem, a Bukidnon-born fighter who trains for the famed ALA Boxing stable.
According to a report by PhilBoxing.com, Jerusalem was deducted a point in the 8th round for a low blow that may have cost him a chance at a draw. He had been warned for the same infraction in the 2nd round.
Jerusalem was behind in the scorecards heading into the 9th, but he fought his way back in the subsequent rounds hoping to score an upset.
Prior to the bout, the 22-year-old Jerusalem was ranked No. 9 by the World Boxing Council.
Wanheng, 31, is now a perfect 45-0. The Jerusalem fight, held at Phitsanuloke province, is Wanheng's sixth successful defense of the 105-pound championship.
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