Saul "Canelo" Alvarez branded middleweight rival Gennady Golovkin a "hypocrite" on Sunday as their war of words escalated ahead of next month's eagerly anticipated rematch in Las Vegas.
World middleweight king Golovkin and Alvarez will climb into the ropes at the T-Mobile Arena on September 15, a year after their long-awaited first encounter ended in a controversial draw.
A planned rematch in May was cancelled when Alvarez failed a drug test, a development which infuriated Kazakh star Golovkin, who later accused his Mexican rival of doping.
Acrimony between the two camps has simmered ever since, and on Sunday both men traded verbal body blows in comments to reporters at an open workout in front of fans at Los Angeles's Banc of California Stadium.
Alvarez, 28, said the bad blood between the duo made it unlikely that he would ever form a friendship with Golovkin once the fight was over.
"For me that would be very difficult," Alvarez said.
"All of the things that have been said. For me, personally, it's very difficult to leave that door open."
Alvarez also bridled when asked to comment on Golovkin's frequent assertion that his trademark aggressive style had made him popular amongst Mexican boxing fans.
"It's hypocritical," Alvarez said. "He's a hypocrite. Maybe he uses it to get fans. If something tragic were to occur in Mexico, he wouldn't be there."
Alvarez, who fought cagily in the first fight 12 months ago which most neutrals believe Golovkin should have won, also rejected suggestions that his opponent had a more "Mexican" style of boxing.
"There's no defined Mexican style," Alvarez said. "There have been many fighters from Mexico who have different styles. My style is mine, I'm Mexican."
Alvarez meanwhile said he is confident that Golovkin has not yet seen the best of him. "He doesn't know what I have left to show," he said.
Trainer Eddy Reynoso also waded in to the verbal dust-up, saying the 36-year-old Golovkin had little room for improvement.
"At (36) years of age, there's nothing else you can teach this guy," he said. "But they have taught him how to run his mouth off."
Golovkin meanwhile earlier accused Alvarez of disrespecting boxing through his failed drug test, which the Mexican's camp blamed on contaminated meat.
The controversy has ensured Golovkin will be carrying a grudge into the ring next month, he said.
"Right now I feel a little bit different," Golovkin said. "It's not only sport, not only business. It's special. Because his team doesn't respect boxing people. This whole situation was terrible.
"I don't feel angry. I don't feel respect for this team, not only for Canelo. He has scandal. You know, he's still working with these people who bring this situation, for this scandal. This is very terrible for him. This is my point.
"And I feel very comfortable because I have my team. I respect my team. I respect my people. I respect the people who support me because this is a true guy. If you're fake, of course you support Canelo. If you’re a real guy, you support me."