Gennady Golovkin: Mayweather vs. McGregor is nothing but "a circus"

Golovkin gives Canelo 50/50 chance: 'I'm not superman' (1:10)

Gennady Golovkin says Canelo Alvarez is his biggest challenge yet and capable of ending his unbeaten streak. (1:10)

Gennady Golovkin sees no threat to his Sep 16 fight against Saul 'Canelo' Alvarez from Floyd Mayweather Jr's comeback against Conor McGregor, which he branded "a circus".

The WBC-IBF-WBA world middleweight champion was talking up the significance of his fight with Canelo on the first leg of a global media tour in London on Monday, after it was announced last week that Mayweather will fight UFC star Conor McGregor at the same Las Vegas venue -- the T-Mobile Arena -- on Aug 26.

Mayweather-McGregor is expected to do astronomical numbers for revenue and television viewers, but its competitive value is questionable.

Even though five-weight world champion Mayweather is 40 and 'retired' for almost two years, the American is the best boxer for a generation and is a huge betting favourite against 27-year-old Irishman McGregor, a mixed martial arts fighter who has never had a professional boxing fight.

Kazakhstan's California-based Golovkin, 35, who has made 18 successive world title defences and is ESPN's pound-for-pound No 1, dismissed the threat of Mayweather-McGregor overshadowing his fight with Canelo and damaging pay-per-view sales.

"This [Mayweather-McGregor] is not for fighters, but business," Golovkin told reporters at a press conference in London Monday.

"I think people understand what is a true fight, a boxing fight, like mine with Caneno or a big show, maybe sometimes for people a funny show, like a circus show.

"Everybody knows -- Conor is not boxer, just show. If you want to watch a show please watch them, if you want to watch a true fight, a true boxing fight and you respect boxing, watch my fight with Canelo.

"This is business. Conor with Floyd is not a boxing fight because Conor is not a boxer. Money fight OK, show fight OK."

Alvarez, 26, lost a majority decision to American Mayweather -- now 40 -- in 2013 and the Mexican says his fight with Triple G instead sees two fighters in their prime against each other.

"This is the fight the fans wanted, demanded," Alvarez told reporters in London.

"They demanded the fight, so to question whether they're going to see it or not, there shouldn't be a question. This is the fight that was demanded and we're happy to give it to them.

"It's two fighters at their best, their peak, and a very high level, and they're going to be fighting each other and giving their best, so the fans are the ones who are going to enjoy this fight."