Kang already had nine birdies against one bogey when his approach to the par-5 closing hole at TPC Summerlin finished 18 feet from the cup and he made the eagle putt.

"Last few weeks I wasn't driving it very good, but my iron play was pretty sharp and my putting was pretty good," Kang said.

"So I was just thinking if I can get my driver somewhere in play I could actually score better."

Fellow South Korean Sungjae Im made five straight birdies on the back nine and, along with an eight-foot eagle putt on No.9, shot a 63. He was joined by Americans Charley Hoffman and Chad Ramey, who birdied all but two holes after the turn.

Matthew Wolff, who lost in a playoff last year at the TPC Summerlin, was among those at seven under (64) along with Matt Jones.

Jones is the leading Australian in the field which includes Cam Davis (67), Marc Leishman (67) and Adam Scott (70).

Sam Burns, coming off a victory last week in Mississippi, was poised to move closer to the lead until his tee shot on the par-3 17th hole found the water. He made double bogey – this after four straight birdies – and had to settle for a 66.

Las Vegas marked the return of six more Ryder Cup players and the Europeans seemed to fare well. Viktor Hovland had a 67, with Paul Casey shooting a 68 and Ian Poulter a 69.

Brooks Koepka also enjoyed a 68, while Harris English was at even-par (71) and Scottie Scheffler opened with a 74.

The low scoring was not a surprise – it took seven-under to make the cut last year – especially in such calm, warm conditions.

"You get no wind, you can start attacking this golf course," said Hoffman, who played golf at UNLV and lived in town until recently moving back home to San Diego.

"It starts blowing 15 to 20 (mph), it's a different animal."