Marcos Maidana has labelled Floyd Mayweather a "baby girl" following their fight at the MGM Grand in Las Vegas last weekend.
The 30-year-old was convinced he had beaten the WBC welterweight champion, but the judges ruled in favour of Mayweather, who did enough on the night to keep his unbeaten record intact.
However, Maidana was not impressed with his opponent, who some consider to be the greatest boxer of all time, and is desperate to secure a rematch.
"I want a rematch now," the Argentine told Clarin newspaper, before ranting: “Mayweather is a baby girl, all the time trying to find excuses.
"Rivals who fight him are intimidated with the show he puts on but it is not what it seems. Every time I hit him he did not know [what] to do."
Maidana also fired back at pop star Justin Bieber, who accused Maidana of using dirty tactics during Saturday's fight.
"To win a fight you have to do everything, but that knee slipped," the South American told Bieber, who accompanied Mayweather into the ring along with rapper Lil Wayne.
The chances of Mayweather agreeing to a rematch with Maidana appear slim, but the stubborn Argentine will not give up without a fight, it seems.