Liam Wilson has accused rival Emanuel Navarrete of tampering with the scales to make weight for their world title fight in Phoenix.
The Australian caused a stir at Thursday's weigh-in when he tipped the scales at 126.3 pounds (57.29kg), almost three pounds lighter than the Mexican favourite and four pounds (almost 2kg) under the super featherweight limit.
A bemused Wilson said he had weighed in almost four pounds heavier on the same set of scales just 20 minutes before the official weigh-in for the WBO strap at Desert Diamond Arena.
He then used the same scales to weigh himself again about 30 minutes after the official weigh-in, albeit after he had drunk water and done a medical test, and had blown out to 132.3 pounds.
The Brisbane pugilist, who had firmed after beginning as an $18 outsider to upset the two-division champion for the vacant belt on Friday night (Saturday AEDT), looked nervy on stage and appeared slightly off colour when speaking to media shortly afterwards.
He was also noticeably leaner than the favourite, but Wilson insists it was he who was sitting just below the 130-pound limit and not the heavier Navarrete.
"I think he (Navarrete) didn't make weight and they've tampered with the scales for sure," Wilson said.
"It doesn't make sense; I didn't lose four pounds in 20 minutes ... I have never been that light in the last 10 years.
"I was waiting in a room 10 metres away (after weighing in unofficially); in that time they must have realised he couldn't make the weight and they've tampered with it.
"It's pretty evident that it's happened."
If Navarrete, unbeaten in 10 years with titles at two lighter divisions, had weighed in over the limit he would have been unable to claim the title, leaving Wilson with a free swing at the belt if the fight still went ahead.
The Mexican's hall of fame promoter Bob Arum rubbished what he labelled a "conspiracy theory", when told of Wilson's allegations.
"Oh come on, this is Arizona, nobody f***s with the scales," the Top Rank boss said.
"Everyone else (on the card) made the weight for Christ's sake, there were no other aberrations.
"I hate all these conspiracy theories in boxing for whatever reason ... let me assure you the scales were accurate."
The fight will go ahead as planned, Wilson no stranger to weigh-in dramas after his nemesis Joe Noynay was almost 4kg too heavy for their rematch last year.
They fought anyway, Wilson knocking the Filipino out to correct his world title path.
Wilson got his chance in Phoenix after high-profile Oscar Valdez sustained an injury and he was catapulted from a world title eliminator bout straight into the big time in his 13th professional fight.
The 26-year-old impressed during the build-up, oozing confidence as he stood over his shorter opponent at Wednesday's first meeting.
"This is a meaningful fight to me; I respect the sport and believe he should," Wilson said.
"No, he shouldn't be (challenging for the title because he was over-weight).
"But it's easy for me to say. I'm not an official, but something happened on the scales.
"It just shows that ultimately he took me lightly, didn't take the training seriously and it's going to show come tomorrow night."
