Jeff Knox isn't in the Masters field, but he turned some eyes during the third round Saturday -- including those of former world No. 1 Rory McIlroy.

Jeff Knox, an Augusta National member chosen to serve as a marker Saturday, bested Rory McIlroy by a shot during the third round. He carded a 70. AP Photo/Darron Cummings

Knox, an Augusta National member, served as a non-competing marker with McIlroy because an odd number of players made the cut. And he showed the Northern Irishman a thing or two about one of golf's famed courses, shooting a 2-under 70 that actually bested McIlroy's score by one stroke.

"He obviously knows this place so well and gets it around," McIlroy said. "I don't think I've ever seen anyone putt the greens as well as he does around here. He was really impressive. I was thinking of maybe getting him to read a few of my putts out there."

McIlroy birdied three of the final four holes in his third round for a 71. Knox bogeyed No. 18 for the 70.

"I thought he was going to be nice and three-putt the last and we would have a half, but he beat me by one," McIlroy said.

Knox's success at Augusta National is no surprise. He holds the member course record there with a 61. But Saturday's round came from the championship tees and the course set up for a major.

Markers are required in golf when the field has an odd number after the cut. The host course determines whether the marker will play with the single professional or just keep his score.

Information from the Associated Press was used in this report.