Ahead of their September rematch, Gennady Golovkin continued to hit out at Canelo Alvarez as their rivalry continues to get more personal.

The two fought in September last year to a controversial split decision draw with many believing Golovkin had done enough to win via decision.

Golovkin and his team have since regularly hit out at Alvarez for "running" during the contest and not fighting in true Mexican style. Alvarez would later test positive for clenbuterol in February, resulting in a six-month suspension and their May rematch getting postponed to Sept. 15.

That only made things more personal as "GGG" claimed his Mexican opponent had been using performance enhancing drugs for a long time as Alvarez, who failed his first-ever drug tests, was arguing that the traces of clenbuterol came from contaminated Mexican meat he had consumed.

"He is the most unpleasant and dirtiest opponent I've ever had," Golovkin said via a translator during a media workout Thursday in Big Bear, California, where he trains. "We have two different styles of boxing. He probably thinks what his style of boxing is, is called boxing."

"I have a completely different style of boxing. What I believe and hope in this upcoming fight will come to this style of boxing which will allow us to finish this fight early."

The unbeaten Golovkin was not serious throughout though. Even though he did not want to do media work, he joked that he may have to lose so he won't get interrupted during his training.

"I remember one very famous athlete said to his coach, 'why are they coming and interrupting me all the time?' and the coach responded 'You should lose once and they will never come,'" he added with a smile.

Regardless, his previous comments only further show how personal this rivalry has become. In the first fight, there was mutual respect, but that's clearly gone out the window this time after the comments both sides have made since about each other.

Alvarez's failed drug tests saw Golovkin fight Vanes Martirosyan on short notice to remain active and later get stripped of his IBF middleweight title even though he was granted an exception. The Kazakh later fought hard to get a more even split of the rematch which almost saw negotiations collapse.

Alvarez meanwhile, says he lost whatever respect he had for Golovkin, as the former's promoter Oscar de la Hoya says the Mexican will be fighting with "anger" in the rematch this time.

"I expect a tough fight for both," De La Hoya said in June. "The fact that Canelo has that anger towards Golovkin, this fight is very personal for both, but the fact that GGG has been talking too much about Canelo, for me Canelo is going to be very motivated, he's going to train harder than ever. For me this fight will be tough, but obviously we are with Canelo 100 percent."