The way Straight Blast Gym Ireland head John Kavanagh sees it, Dustin Poirier is facing a very strong mental challenge in his upcoming rematch with Conor McGregor.

Even though it’s been more than six years since the two first met, Kavanagh believes that initial pairing, which McGregor (22-4 MMA, 10-2 UFC) won via first-round TKO, will weigh heavily on Poirier (26-6 MMA, 18-5 UFC) at UFC 257.

“I think you can spend a lifetime going to sports psychologists and talking to this person and that person; that’s not going to have been erased from his mind,” Kavanagh recently told TheMacLife. “He knows that he is facing somebody who can shut off his lights very, very rapidly and now is a lot more powerful and a lot more experienced than he was even then, so it’s a tough, uphill battle for Dustin.”

McGregor’s longtime head coach, Kavanagh was in charge of preparing for Poirier in 2014, and he’s been tasked with the challenge again, ahead of their Jan. 23 pay-per-view headliner in Abu Dhabi. Of course, much has changed with both fighters in the interim, which is what makes the rematch so intriguing.

Kavanagh knows they can’t simply prepare for the same fighter they faced before but thinks that mental edge will be difficult to overcome.

“I think (Poirier) has definitely gotten better,” Kavanagh said. “There’s a few more takedown attempts now in his fights. I hadn’t seen it before – he has a good guillotine. We can see that. Then his volume and his conditioning is looking on point. You can see in his fights he has an ability to take a lot of punishment and still come forward. Pick any of last few fights to see that quality. However, he’s fighting a different animal than any of those guys: somebody with true, one-punch knockout power that he’s already felt.”

Of course, there are arguments to be made for things that might fall in Poirier’s favor. After all, it’s generally accepted that he was physically depleted in their first encounter, contested in the featherweight division, and that “The Diamond” will be able to handle McGregor’s power a little better at 155 pounds.

Poirier has also added a bit more cage time to his arsenal, making 13 walks to the octagon since then as opposed to McGregor’s eight.

Kavanagh acknowledges those factors, as well, but believes McGregor’s initial domination speaks volumes as to how the rematch will play out, as well.

“It was a bad night for Dustin,” Kavanagh said. “It was very one-sided, and when you look at some of the shots he’s absorbed – now he’s a bigger man now, and you can say maybe there’s some argument he can absorb more shots now, but he’s fighting a bigger man, as well. Even if you remember back to the fight, the opening hook kick, it just whistled by his head. A couple of inches lower, that might have even outdone the Aldo fight.

“So look, they’ve both matured physically. Age-wise, you know, they’re in their 30s now and (have) families. Dustin’s had a couple of more contests then Conor since then in the octagon. Conor’s never stopped training and has obviously had a boxing match and has done other stuff, so it’s interesting to see how the styles meet up this time.”