By Keith Idec

LAS VEGAS – Sergey Lipinets needed one punch and less than two rounds to take out Javar Inson on Saturday night.

Kazakhstan’s Lipinets leveled Inson with a crushing left hook to the side of his head that sent Inson face first to the canvas. Inson reached his feet and wanted to continue, but referee Jay Nady decided he shouldn’t continue.

Nady stopped the action 57 seconds into the second round on the Manny Pacquiao-Keith Thurman undercard at MGM Grand Garden Arena.

The 30-year-old Lipinets (16-1, 12 KOs) won his third straight bout since suffering his lone loss – a 12-round unanimous decision to Mikey Garcia 16 months ago in San Antonio. The 28-year-old Inson (18-3, 12 KOs), who’s promoted by Pacquiao, lost by knockout for the first time since he turned pro in December 2013.

Lipinets was supposed to face veteran John Molina Jr. on Saturday night. The 36-year-old Molina (30-8, 24 KOs), of Covina, California, pulled out of their fight Friday morning due to a back injury.

Inson agreed to face the former IBF junior welterweight champion on about 36 hours’ notice. Lipinets agreed to fight a southpaw without having sparred against left-handed opponents during this training camp, but Inson had never fought anyone on Lipinets’ level.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.