There has been a lot of conversation regarding the possibility that UFC superstar Conor McGregor may get frustrated during his upcoming boxing match with Floyd Mayweather - and then resort to illegal tactics, like an elbow to the face.

McGregor is making his professional boxing debut on August 26, when he takes on Mayweather (49-0, 26 KOs) at the T-Mobile Arena in Las Vegas.

But one boxer says it's McGregor who should be worried about receiving an elbow to the face.

Former welterweight champion Victor Ortiz remembers when he fought Mayweather in 2011. Ortiz, who returns to the ring on Sunday, says Mayweather was blasting him with elbows throughout their fight. Ortiz says he eventually lost his cool in the fourth round and intentionally head-butted Mayweather. In the infamous outcome, Ortiz went over to apologize to Mayweather and get blasted with a combination that knocked him out.

Ironically the referee for the contest was Joe Cortez, who is currently a member of McGregor's camp and teaching the MMA fighter the rules of boxing.

“You can’t elbow unless you are Mayweather,” Ortiz told USA Today. “I think on both parts we both had a lot of mistakes taking place. He was hitting me with his elbows. I took a lot of them. I took I believe 16 or 17. I kept telling Cortez, ‘Hey Cortez, elbow, elbow.’ (He just said) ‘Keep fighting Ortiz, keep fighting Ortiz.’

“(I was) trying but then it got to the point where I felt like I was seeing double out of one eye and I think that’s your retina when that is happening. The other eye was starting to swell, not from the punch. He (elbowed) and got away with it. I think what I did was wrong, I headbutted. I ended up paying ugly.”