Liborio Solis, stripped of his WBA super-flyweight champion belt overnight for being overweight, beat IBF holder Daiki Kameda on a split decision in what would have been a unification title bout in Osaka Tuesday.
Venezuelan Solis failed to make the 52.1-kilogramme limit in Monday's weigh-in and lost his World Boxing Association title in the division.
The 24-year-old Kameda retained his International Boxing Federation crown, officials said after the bout. According to a pre-match announcement, the two titles would have been left vacant if Solis defeated the Japanese.
There was no knockdown in the 12-round bout at the Osaka Bodymaker Colosseum, with the two boxers exchanging blows in close range.
Three US judges gave a 3-1 decision with Joe Garcia and Valerie Dorsett scoring 116-112 in favour of Solis. Robert Hoyle carded Kameda the winner by 115-113.
"It makes me feel happy to win but unfortunately I could not unify the title," Solis told reporters through an interpreter. "I feel responsible for my failure to make the weight."
In earlier matches at the colosseum, Kameda's younger brother Tomoki, 22, beat Namibian challenger Immanuel Naidjala on a 3-0 decision to retain his World Boxing Organisation bantamweight title.
Another Japanese, Katsunari Takayama, overwhelmed Philippine challenger Virgilio Silvano with a unanimous decision for him to retain his International Boxing Federation minimumweight title.
The 31-year-old Solis came out fighting with both hands despite his failure to make the weight. Kameda's nose started to bleed in the third round when Solis punished him with one-two combinations and uppercuts to the body.
Kameda relied on clenchwork to stop Solis from boring in the late rounds.
For Kameda, it was his fourth defeat in a career studded with 29 wins, 18 of them by knockout. Solis stretched his record to 16 wins, seven of them inside the distance, against three losses and one draw.
The weigh-in on Monday bordered on the farcical.
In his first weigh-in, Solis was 1.4 kg above the 52.1 kg limit.
Solis was still 1.1 kg overweight in his second weigh-in an hour later and he refused to step on the scales for a third time inside the two-hour time limit to make the weight.
As soon as he gave up his attempt, Solis was seen gulping down water from a plastic bottle and buying cans and bottles of soft drinks from a vending machine, Japanese media said.
"I won't reduce my weight any more. I cannot make it because it is too cold in Japan," he was quoted as saying.
"I ran for one hour but it didn't help. I cannot sweat any more if I move around for another hour."
The WBA is expected to fine him for his failure and he will have to return his fight money to promoters.
"I will pay it back in pesos or anything," said the Venezuelan boxer.
Kameda, who has reduced his weight by 11 kg, said: "It will be great if I can recover in time and finish him off with a clean knockout."