By Bob Harig of ESPN.com

ST. ANDREWS, Scotland -- Jordan Spieth's Grand Slam dream is still alive.

Spieth saw to that Sunday at the Old Course, where his 6-under-par 66 in the third round put him near the top of the leaderboard at The Open.

The 21-year-old Spieth is at 11-under overall and will enter Monday's final round trailing amateur Paul Dunne, Jason Day and 2010 Open champion Louis Oosthuizen by a stroke.

"At this point it's free rolling," Spieth said. "I'm going to play to win -- I'm not playing for a place. I don't want to place third tomorrow. I want to win.

"I'm going to play my game, obviously with patience, to stay in the mix if it's not all there in the beginning. And if it is, I'm going to continue to play that way to try and get out in front. Just trying to give myself as many chances as I can."

Spieth, who won the Masters and U.S. Open, is in the best position since Jack Nicklaus in 1972 to win the third leg of the Grand Slam. Nicklaus was 6 strokes behind Lee Trevino entering the final round and ultimately finished a shot back in The Open that year.

Prior to that, Arnold Palmer trailed by four entering the final round at St. Andrews in 1960, only to finish a stroke behind Kel Nagle. In 2002, Tiger Woods won the first two majors, but a third-round 81 dropped him 11 strokes back going into the final round.

Ben Hogan is the only player to win the Masters, U.S. Open and The Open in the same year. He accomplished the feat in 1953, the only time he played The Open.

"I see this as something that's only been done once before, and it was a long time ago," Spieth said. "That opportunity very rarely comes around. I do recognize what's at stake."

Spieth will be chasing a trio of players with varying resumes on Monday.

Dunne is from Ireland and played college golf at the University of Alabama-Birmingham. He made it to The Open by winning a local qualifier two weeks ago and shot 66 during the third round.

Day, a frequent contender in majors including last month's U.S. Open, shot 67 on Sunday. Oosthuizen, who won The Open here five years ago and lost in a playoff to Bubba Watson at the 2012 Masters, also shot 67.

Spieth began the day five strokes behind second-round leader Dustin Johnson and walked off the ninth green angry after missing a short putt for bogey that left him 7-under for the tournament.

But he rattled off three straight birdies at the 10th, 11th and 12th, saved par from off the green at the 13th, birdied the 15th and made another nice save at the 17th. After five 3-putts in the second round, he had five 1-putts in a six-hole stretch on the back nine Sunday.

"I'm very pleased with putting myself in position," Spieth said. "Really happy to at least get back into it."

Spieth became the first player since Woods to win the Masters and U.S. Open in the same year. He won the U.S. Open last month at Chambers Bay when Johnson 3-putted the final green. He is coming off a victory a week ago at the John Deere Classic, his fourth of the year on the PGA Tour.