Phil Daru recognized Dustin Poirier’s transformation well before his most recent fight, a five-round slugfest with Dan Hooker in June.

Their battle showcased Poirier’s strength, mettle and durability in a unanimous victory several months after he underwent hip surgery. Daru, Poirier’s strength and conditioning coach, believed it reestablished the brawler nine months after he lost to lightweight champion Khabib Nurmagomedov and six years after his loss to Conor McGregor pushed him into the division.

“The fight with Hooker showed that he’s still a force to be reckoned with inside that cage,” Daru said. “That was one thing that really stood out to me was his ability to finish fights when he sees the time to do so.”

Six years ago, Poirier (26-6) couldn’t finish his fight with McGregor. He couldn’t even finish the first round before the Irishman grazed him with his left hand and was declared the winner 106 seconds into the fight, handing Poirier his first defeat by TKO. On Saturday, in the main event of UFC 257 in Abu Dhabi, he’ll get another shot.

The loss inspired maturation in Poirier, who has said he became more grounded and more composed. The birth of his daughter in 2016 helped him prioritize what’s important.

Losing to McGregor also inspired a physical change, compelling Poirier to jump from featherweight to lightweight, where the maximum weight increased from 145 to 155 pounds, enabling him to shed and maintain mass more comfortably.

“I’m more athletic at this weight, and this is much closer to my actual weight. My body is just performing very well. I should have been here; this is the optimal weight class for my body to perform at its max. My power, my speed, everything feels better,” he told Fox Sports in 2015.

George Lockhart, Poirier’s former nutritionist, described the fighter’s process preparing for a featherweight bout to Men’s Journal several years ago, detailing a pre-fight camp during which Poirier’s diet, portions and hydration were strictly controlled to drop roughly 40 pounds in two to three months — a routine that left him feeling “dizzy” and depleted (via MMA Junkie).

“You’re dieting down. You’re depriving your body of its nutrients that it needs, especially for fight camp. You’re not getting an adequate amount of fuel, so you’re always tired, pretty lethargic,” Daru said. “I think moving to 155 made him way more durable, gave him more excitement to be in camp instead of having to worry all the time about his weight.”

That shift powered Poirier to four straight wins in 2015 and 2016, three of which came by first-round knockout. Entering Saturday he has won five of his past six contests, highlighted by a fourth-round knockout of Justin Gaethje and an interim lightweight title victory over Max Holloway. He suffered his only loss of that stretch when he failed to unify the title against an undefeated Nurmagomedov in 2019.

“Six years since we fought, you have to evolve to stay at the top of the division for this long, to stay in the company for this long,” Poirier said during Thursday’s pre-fight news conference, which featured far more compliments than jibes between him and McGregor.

He said his technical maturity is the biggest difference from their last fight.

Well, that and one other thing.

“I don’t care what anyone out here thinks anymore,” he said. “I used to care too much. I don’t care; that’s a superpower — not giving a [expletive].”

But in the six years in which Poirier rebuilt and reassessed, McGregor (22-4) transformed his body and legacy, too.

The win over Poirier fueled McGregor’s ascension. He went on to claim the interim featherweight belt against Chad Mendes, then took just 13 seconds to knock out Jose Aldo to unify the title. He demolished Eddie Alvarez in a lightweight title bout to become the first fighter to hold two belts simultaneously in 2016.

Over the next four years, McGregor’s bravado and skill begot lucrative opportunities, but he consistently courted controversy.

He was guaranteed $30 million for his 2017 boxing match against Floyd Mayweather Jr., which he lost by 10th-round TKO. His 2018 lightweight title challenge against Nurmagomedov proved unsuccessful, ending in a fourth-round submission and a post-fight skirmish that resulted in a six-month suspension.

McGregor did not step into the octagon in a tumultuous 2019 during which he was arrested for “stomping” on a man’s cellphone, was shown hitting a man in a Dublin bar, and faced questions about sexual assault allegations revealed by the New York Times — one of which led to a lawsuit filed against McGregor in Ireland on Monday.

The Irishman hoped to fight three times in 2020 but settled for a single bout, during which he quickly dispatched a waning Donald Cerrone last January before the pandemic curbed his plans. It was his first win in two UFC fights over the past four years.

Entering Saturday’s bout, Poirier knows the challenge ahead and is amply aware of McGregor’s lurking left hand and its concussive bite.

In the rematch, he’s less drawn to revenge and more focused on the climb back into the lightweight title chase.