Turns out there's another 21-year-old American called Jordan to watch out for at the British Open.

Jordan Niebrugge shot the lowest first-round score by an amateur in the Open at St. Andrews with a 5-under 67 on Thursday, ensuring he was keeping Grand Slam-chasing Jordan Spieth company on the leaderboard.

Niebrugge's parents — dad Rod and mum Judy — were there to see their son's first round at a British Open after qualifying for golf's oldest major last month. They weren't surprised to see him play so well, given his liking for and experience in links conditions back home in Wisconsin.

"It's a cool way to play," said Niebrugge, who took advantage of benign morning conditions to pick up shots on the first and last holes and birdie five more holes on the Old Course. "It's not target golf, like back in the States. Just to play around here and use your imagination is cool."

Niebrugge played in the Walker Cup in 2013 and is one of the rising talents in the United States. But he has said he will not turn professional until 2016 after he finishes his degree in entrepreneurship at Oklahoma State, the university that counts Rickie Fowler, Hunter Mahan and Scott Verplank among its golfing alumni.

Niebrugge appears to have an old head on young shoulders, much like Spieth — the current Masters and U.S. Open champion.

"I feel like he's just got the most confidence in the world and that's what you need in this sport," Niebrugge said of Spieth. "That's what everyone strives for. Definitely looking up to him and following in his footsteps just gives me that extra motivation."

Wearing a bright pink winter coat, Judy Niebrugge was easy to spot for her son as she walked the course on a cool, cloudy morning. Niebrugge's parents were also over for three weeks last month, when he competed in the British Amateurs, the Brabazon Trophy (an English amateur championship) and then final qualifying for the British Open.

Niebrugge shot 69 and 72 to tie for first place at Hillside, near Liverpool, and qualify for his second major after the Masters in 2014.

"He's been in this situation before, at the Masters and the Walker Cup, so I'm not really surprised," a proud-looking Rod Niebrugge said by the 18th green.

"He is pretty comfortable in this type of course and this type of weather is not unusual for him. He plays in wind in Oklahoma State and has played in snow in Wisconsin during high school in spring season. Obviously we didn't expect the 67 out of him, but he always had a chance of doing well."

Other amateurs were doing well on Thursday, too.

Paul Kinnear, a 20-year-old from Liverpool who also came through final qualifying, reached the turn at 5 under par. Ireland's Paul Dunne shot 69 and 22-year-old American Oliver Schniederjans had a 70.