Jordan Spieth at British Open 2015: Thursday Leaderboard Score, Twitter Reaction

Jordan Spieth carded an opening-round five-under 67 to put himself two shots away from clubhouse leader Dustin Johnson at the 2015 British Open, maintaining his hopes of becoming the second person ever to win three majors in a single season.

He took long strides toward matching the 1953 achievement of Ben Hogan with an assertive first day on the St Andrews course. The reigning Masters and U.S. Open champion shot an excellent five-under front nine to initially put himself among the leaders.

He is currently poised to challenge for the Claret Jug, highlighted by the official rankings:

You can check out the full leaderboard on the British Open's website.

Spieth began the day with two birdies, easing his way into proceedings with a snapshot of the calm, calculated quality that makes him so competitive. He parred the third and fourth holes, showing slight disappointment on the former, undoubtedly an indicator of the expectation now placed on his shoulders.

However, the youngster gained a shot on each of his next three holes, highlighted by the European Tour's official Twitter feed:

Spieth rounded off his front nine with two more pars to put himself at five under at the turn. ESPN highlighted the player's fast start and how it compared to his previous victories:

PGATour.com provided a highlights package of Spieth's opening descent onto the course: 

At this point, the initial showing of three-time Open Championship winner Tiger Woods was put into perspective by the Telegraph's Paul Hayward:

Sam Borden of the New York Times added to Woods' misery:

Spieth continued in confident fashion during a breezy, overcast day at St Andrews. He gained another shot on the 11th before finding a bunker on the approach to 13. This led to his first bogey of the tournament, pushing him just below the leading pack, noted by the PGA Tour's official Twitter feed:

However, Spieth's self-belief and confidence never wavered. He settled himself well, hitting three consecutive pars before losing another shot on 17. Jason Sobel of ESPN commented on Spieth's journey through a difficult hole:

In typical style, Spieth quickly regained his composure and sunk an excellent putt to birdie 18, a brilliant way to round off his day.

"I don't feel intimidated by anybody," said Spieth heading into Thursday's play, per Ben Dirs of BBC Sport. "Whoever is up at the top of the leaderboard, I want to knock them off." This showed in his remarkable consistency and, when trouble arose on 13, his ability to keep things under control.

Jon Super/Associated Press

It's this natural maturity that makes the American such a dominant force at the tender age of 21. He understands people expect him to perform, a notion amplified when Rory McIlroy dropped out of the competition through injury, as reported by Iain Carter of BBC Sport. Yet there's an unflinching coolness about Spieth's game.

However, he needs to remain focused heading into the rest of the competition. Pressure is mounting, but Spieth is yet to show any signs of fear in front of the British crowd. He makes each hole look shorter and wider when he plays to his full potential, something he will be eager to achieve at the onset of Friday.