|Pongsaklek drums a rhythm on Kameda's chin [AFP]
Koki Kameda's self-predicted reign of terror ended swiftly in his first defence as he lost a points decision to Thailand's Pongsaklek Wongjongkam in front of his home crowd in Tokyo.
The defeat to the veteran Thai came just four months after Japan's boxing bad-boy won the WBC flyweight title from popular countryman Daisuke Naito.
Kameda entered the ring wearing a silver hooded top with purple fur trim to the theme tune from Rocky IV but he failed to live up to his own pre-fight hype.
A clash of heads at the start of the fifth round opened a nasty gash above Kameda's right eye and the 23-year-old continued with blood streaming down his face and chest.
"I kept calm and the fight went perfectly to plan," Pongsaklek, 32, said.
"I didn't want to pass the torch to the next generation by losing tonight."
Kameda bowed to the crowd in apology after seeing his opponent's arm raised by the referee.
Pongsaklek, who won a flyweight-division record 17 title defences before his shock defeat by Naito in July 2007, almost ended the fight early with a flurry of big punches.
He shook the champion with a fierce uppercut at the start of the 11th and a wincing Kameda almost went down when he was caught by another heavy blow near the end of the final round.
Pongsaklek – who had quietly climbed into the ring wearing a simple, red bobble hat in contrast to Kameda's flashy entrance – was awarded the fight 116-112 and 115-112 by two of the ringside judges with the third surprisingly scoring the contest even at 114-114.
Kameda, who was employed as a sparring partner for Pongsaklek while in his teens, tasted defeat for the first time in 23 professional contests.
In October 2007, Kameda's younger brother Daiki challenged Naito, wrestling the champion to the canvas in his failed title bid.
Daiki was suspended for a year and Koki was reprimanded by the Japan Boxing Commission for urging his brother to fight dirty.
His father Shiro Kameda, then a trainer, was also banned from being a cornerman.
Pongsaklek became the champion in March 2001 and held a winning streak to 56 before losing to Naito by a unanimous decision in July 2007.
Saturday's fight saw him better his record to 75 wins, including 39 KOs, against three defeats and a draw.