Chris Eubank Jr has urged Gennady Golovkin to take him on in a "real fight" after the latter's bout against Kell Brook.
Eubank Jr was looking to challenge the WBA Super, WBC and IBF world middleweight champion, before the deal collapsed after weeks of negotiations.
Golovkin (35-0-KO32) will now fight Brook (36-0-KO25) live on Sky Sports Box Office at The O2, on September 10.
Eubank Jr previously labelled the Kazakhstani's decision to face Brook a 'joke' and he has now continued his war of words on social media by again criticising the upcoming clash.
He said on Twitter: "GGG when you're done with the child's play, I'm ready & waiting to take those belts off you in a REAL fight.
"Oh & I'm in the same weight class as you so it will be fair #Fraud #SayNoToBullying."
Brook has not fought for a title above 147lbs in his career, but jumped at the chance to move up two weight divisions to 160lbs.
Golovkin's promoter Tom Loeffler said the Sheffield man took just 48 hours to agree terms, following protracted talks with Eubank Jr.
Eddie Hearn believed the "impossible" demands made by Eubank Jr and Sr were the reason behind their failure to finalise a deal with Golovkin, but admitted there could be an opportunity for the Eubanks to eventually get the fight they want.
Hearn told Sky Sports News HQ: "There is a huge future for Chris Eubank Jr. He can fight the winner later on in the year.
"He has got a big future ahead of him. He misses out this time but I am sure he will get his shot in due course."