Floyd Mayweather, the undefeated boxer and master of the diss, unknowingly provided a slap in the face to MMA star Ronda Rousey during a recent interview.

After UFC president Dana White said Rousey could "hurt Mayweather badly" and Rousey said she could hang with Mayweather in an MMA fight, reporters were eager to ask Mayweather what he thought about challenging the 27-year-old former Olympian.

Mayweather, who is on a tour promoting his September rematch with Marcos Maidana, appears to not know who Rousey is.

It should be noted that Mayweather is a master showman, and he may be pulling a fast one here. It would be pretty surprising if he didn't actually know who Rousey is, not only because of what she and White said but because Rousey is a high-profile fighter who has even has filmed several movies (although none have been released yet).

Or, perhaps Mayweather is truly unaware of Rousey. The man runs a $100 million-per-year enterprise and maybe he's too busy to have read up on Rousey.

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