Floyd Mayweather Sr. Rips Justin Bieber for Saying Conor McGregor Will Avoid KO

Frank Franklin II/Associated Press

Floyd Mayweather Sr. had some choice words for Justin Bieber after the singer said he thought Conor McGregor would be able to avoid being knocked out by Floyd Mayweather Jr. in their boxing match on Aug. 26. 

Speaking to TMZ Sports, the elder Mayweather said Bieber "don't even know boxing" and "he don't know Floyd like I know him."

Bieber told TMZ Sports on Tuesday "I don't think so" when asked if he believes Mayweather will be able to knock out McGregor, though he also added he expects it to be a good fight. 

Mayweather and Bieber have been on good terms for some time, with Bieber being in Money's corner multiple times, including for the 2015 fight against Manny Pacquiao. 

Even though McGregor is making his professional boxing debut in this fight, a knockout win by Mayweather would be a surprise. The 40-year-old has won just 26 of his 49 career fights via knockout or TKO, with only one of those coming in nine fights since 2010. 

This will be Mayweather's first boxing match since Sept. 2015, when he defeated Andre Berto by unanimous decision.