McGregor gave a brutally honest post-fight interview to Ariel Helwani after suffering his first UFC defeat back in March 2016.
The Irishman entered his UFC 196 main-event bout as a huge favourite over Diaz, who took the fight on short notice.
The Stockton slugger pulled off a massive upset as he submitted the 'Notorious' in the second round.
And speaking after his devastating loss, McGregor admitted he "panicked" when his American foe went into "auto-pilot mode" in a fascinating insight.
"It stings. It stings real bad," he told FOX Sports. "This is the fight business. I've been on the end of many defeats in my life and I've rose back, so I will not shy away from it. I will not make excuses for it. I will assess it and come back."
He added: "I misinterpreted his efficiency. He was very efficient and he took shots well. Played with his energy well, whereas I didn't. I blew out, he did not. Certainly, I felt that I hurt him many times in the fight.
"I abandoned the body shots. The body shots were doing damage but he hit me with one or two shots to the body and I avoided his body then after that.
"He played well. He went into auto-pilot mode and I panicked a little bit. This is it, you win or you learn."
McGregor's post-fight interview was well received by MMA fans.
"One of the most impressive moments of Conors career," one YouTube user wrote.
A second wrote: "Greatest post fight interview after a loss I've ever seen."
A third added: "This gave me a bit more respect for that man."
McGregor, of course, exacted revenge in the rematch five months later as he out-pointed Diaz in an epic five round contest at UFC 202.
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