One constant refrain during the build to UFC 257 and the rematch between Dustin Poirier and Conor McGregor was that Poirier was not the same man he was when McGregor knocked him out in their 2014 featherweight meeting. Poirier proved that to be true in the rematch on Fight Island when he survived early blitzes from McGregor to score a shocking upset victory by second-round knockout.

McGregor came out fast, flashing his trademark speed and power, and even dipping back into the same shoulder strikes that led to the knockout of Donald Cerrone in his January 2020 return to the Octagon. Through it all, Poirier remained steady, working over McGregor with leg kicks, eventually taking the base of the Irish superstar before blitzing him with punches, dropping him to the canvas and scoring the knockout at the 2:32 mark of Round 2.

The leg kick attack was a constant through the round and a half of action, with Poirier never deviating from the plan. When McGregor landed and rocked Poirier's head back, Poirier would reset and immediately look to land the thudding kicks to McGregor's calf.

Once McGregor seemed to have trouble moving effectively, Poirier keyed in and amped up his volume punching.

"The leg kicks were good," McGregor said after the loss. "The lower calf kick was very good. My leg was dead, man."

Poirier's confidence shone through from the early moments of the fight. While McGregor was effective with his offense, Poirier engaged in talk during the fight and even pointed at McGregor after landing a punch, delivering the message that much had changed in the past six years.

"I'm happy, but I'm not surprised," Poirier said after his win. "I put in the work. Conor took this result very professionally over here. He's a pro, man. Nothing but respect. We're 1-1; maybe we have to do it again. I'm just happy in the place I am. I'm happy with the man I see in the mirror. This fight is great. This win is great."

Since lightweight champion Khabib Nurmagomedov announced his retirement after his victory over Justin Gaethje at UFC 254 in October, UFC president Dana White has insisted he believes the champ will return for one final fight. White claimed that someone would have to do something truly impressive to get him to return to the Octagon.

Poirier certainly impressed -- as did Michael Chandler in his knockout of Dan Hooker in the co-main event -- and it would be hard to ask for more than a knockout of the biggest star in the game. Poirier has already lost to Nurmagomedov once, in a fight where he held the interim lightweight title.

Poirier seemed unconcerned with Nurmagomedov's future, declaring himself a champion for the win over McGregor.

"I felt like this was a title fight," Poirier said. "If Khabib's not coming back, me and Conor are the two best guys. I'm the champion."

McGregor is now 1-2 in his UFC career in lightweight fights, having lost to Nurmagomedov and Poirier in his only fights in the division since winning the lightweight title against Eddie Alvarez in November 2016.

While the gameplan of Poirier and failures in his conditioning seemed to be factors in McGregor's defeat, he put the blame for the first knockout loss of his career largely on a lack of consistent activity.

"I need activity, guys, come on," McGregor said. "You don't get away with being inactive in this business. That's just the way it is. I'll take my licks. I'm good at my job."

McGregor has only fought twice in the UFC since 2018, beating Cerrone last year and then losing to Poirier. In between, he has announced multiple retirements and engaged in bitter financial negotiations with the UFC.

McGregor promised more activity moving forward while still struggling to deal with the immediate aftermath of a brutal defeat.

"It's a tough one to swallow," McGregor said. "I put in a lot of work. I'm proud of my work."

Elsewhere on the card, Joanne Calderwood turned in a solid performance with a decision win over former title challenger Jessica Eye in a featured bout. Calderwood, who risked her own shot at the title last year and suffered a first-round submission loss, looked crisp in striking and grappling en route to earning scorecards of 30-27, 30-27 and 29-28. White said afterward that she'll definitely be in the conversation to challenge champ Valentina Shevchenko next.

CBS Sports was with you the entire way on Saturday bringing you all the results and highlights from UFC 257 below.

UFC 257 card and results

Dustin Poirier def. Conor McGregor via second-round TKO (punches)
Michael Chandler def. Dan Hooker via first-round TKO (punches)
Joanne Calderwood def. Jessica Eye via unanimous decision (30-27, 30-27, 29-28)
Makhmud Muradov def. Andrew Sanchez via third-round TKO (punches)
Marina Rodriguez def. Amanda Ribas via second-round knockout (punches)
Arman Tsarukyan vs. Matt Frevola via unanimous decision (30-27, 30-27, 30-26)
Brad Tavares def. Antonio Carlos Junior via unanimous decision (30-27, 30-27, 29-28)
Julianna Pena def. Sara McMann via third-round submission (rear naked choke)
Marcin Prachnio def. Khalil Rountree Jr. via unanimous decision (29-28, 29-28, 29-28)
Movsar Evolev def. Nik Lentz via split decision (28-29, 29-28, 29-28)
Amir Albazi def. Zhalgas Zhumagulov via unanimous decision (29-28, 29-28, 29-28)