In preparation for his professional boxing debut, McGregor has drafted a series of seasoned boxers into his camp, including former pro Paulie Malignaggi who compiled a respectable 36-8 record across his 16-year career.
Malignaggi emerged from their first sparring session in late July with a black eye and remained tight-lipped about McGregor's form in the ring.
But he was more forthcoming after their latest session in the UFC Performance Institute in Las Vegas, telling ESPN that there was a "lot of violence".
"I went in there to prove a point," Malignaggi explained.
Malignaggi was also critical of the fact that the sparring session took place in front of UFC president Dana White and the promotion's former CEO, Lorenzo Fertitta.
"I didn’t like the fact I had to fly across the country on Monday, and they have me scheduled for 12 [rounds] on Tuesday," said Malignaggi, who lives in New York.
"I thought it was a little bit of a set-up. Usually, all sparring is private. I show up at the UFC headquarters and Fertitta is there. Dana White is there.
"So I’m thinking these guys are thinking they’ll catch me right off the flight, set me up for him to look good in front of his audience. I didn’t like that. I kind of went in with a chip on my shoulder."