Dave Allen has strenuously denied his fight with Dorian Darch was fixed.
The popular heavyweight knocked out his journeyman opponent in the third round in Sheffield on Saturday night.
But the British Boxing Board of Control and the Gambling Commission have since launched an investigation into allegations of suspicious betting activity.
According to The Sun, the odds on Allen winning in the third round dropped from 9/2 to evens in the hours before the bout.
The Doncaster man then eased through the opening two rounds before stopping Darch in the third session.
He later said he upped the pace on the instruction of promoter Eddie Hearn who was ringside.
And after accusations the bout was pre-determined, Allen tweeted: "People were saying it was a fix because I was planning on it being a six-round move around.
"A few of my mates had a lot of money on the points win and it didn’t come in but I am not the sort of guy who picks a round to win, I am not really good enough to do that.
"I am a heavy-handed hard b****** and I caught him with a left hook, I stepped off and he said ‘come on’ so I attacked him to the body and put him over. I haven’t lost or made any money on it."
He later added: "The last thing I will say on this is the British boxing board and gambling commission are very welcome to contact me at [sic] there convenience and talk this through and happy to answer all questions and I hope they do this as soon as possible and put the matter to bed."
Darch, whose record reads 12-12-1, tweeted: "Should have chucked a couple of quid on myself if I knew lol.
“People are nuts get hit down once get back up, get wobbled to my boots with a left hook but still dull enough to try and act hard and pretend not to be hurt and call him on and I've taken a dive brilliant.
"Just hard to get your head around butt i know being a journeyman is a job I got f*** all to gain be losing in a certain round I cant bet myself.
"I'm a trying journeymen who got beat in round 3. If I would av covered up like a koala and lost on points would that have been a fix?"
