Poirier knocks out Conor McGregor in second round at UFC 257

In this Sept. 27, 2014, file photo, Conor McGregor, left, kicks Dustin Poirier during their mixed martial arts bout in Las Vegas. (AP Photo/John Locher, File)

ABU DHABI, United Arab Emirates — Dustin Poirier stopped Conor McGregor with a flurry of punches midway through the second round Sunday, avenging his loss to the Irish superstar with a knockout victory at UFC 257.