Conor McGregor has been known to shout his mouth off but at some point, he may encounter someone who have his number. It could be Jose Aldo, whom he has been jawing against for most part of the year, or perhaps someone else.

That someone else could be Joseph Duffy, a 27-year-old mixed martial artist who was born in Donegal but spent most of his childhood in Wales.

What makes him so special? Well, aside from the fact that he is an up-and-coming Ultimate Fighting Championship (UFC) fighter who will someday vie for the UFC featherweight plum, he has something no other fighter in the division can boast of — a win over the trash-talking Irishman.

That feat was, of course, achieved way back in 2010 when he and McGregor faced off at Cage Warriors 39. It took him only 38 seconds to make McGregor submit at the time, a rarity considering McGregor has been racking up the W's since.

A lot has changed since that time, of course, and Duffy is pretty much aware of the improvements that McGregor has had.

Regardless and despite the changes in McGregor's style, the soft-spoken Duffy believes that should he get the chance to face McGregor again in the future, the outcome will still be the same.

Why is he so confident?

Familiarity is what Duffy seems to be leaning on. He knows that McGregor loves to go on the offensive with his kicks and he feels that there is no area where McGregor can defeat him just in case.

While Duffy seems promising, it may be a long road before he gets a chance to get that rematch. But it seems he doesn't mind working his way up, opting to stay out of the limelight (for now).

UFC President Dana White knows what Duffy is capable off and seems to be entertaining the thought of seeing both Irish fighters facing off at some point. The question now is when.