Playing for the first time since his devastating loss at Chambers Bay, Dustin Johnson was hitting on all cylinders in Thursday's first round at the Open Championship.

Johnson fired a 7-under 65 on the Old Course at St. Andrews with five birdies and an eagle. He closed with four pars in a row to cap a bogey-free round.

The WGC-Cadillac Championship winner became the first man since Gary Player in 1974 to lead after first round of both the U.S. Open and the Open Championship in the same year.

Johnson was close to winning his first major title at the U.S. Open at Chambers Bay, but 3-putted for par on the final hole to share second place behind Jordan Spieth.

Spieth, who has won the season's first two majors, was paired with Johnson for the first two rounds. Spieth birdied the 18th on Thursday for a 5-under 67, which left him tied for eighth.

If Spieth were to win this week, he would join Ben Hogan (1953) as the only players to win the first three majors of a season. Spieth claimed his fourth PGA Tour victory of the season last week at the John Deere Classic.

Spieth stands alongside Kevin Na, 2011 Masters champ Charl Schwartzel, amateur Jordan Niebrugge and Louis Oosthuizen, who won this title in 2010, the last time St. Andrews hosted the Open.

Jason Day, one of the other key players at the U.S. Open, is far more healthy this week than he was at Chambers Bay, where he collapsed while battling vertigo.

Day opened with a 6-under 66. He was joined in second place by two-time U.S. Open champ Retief Goosen, 1999 Open champion Paul Lawrie, 2007 Masters winner Zach Johnson, Danny Willett and Robert Streb.

Last year's winner Rory McIlroy is out of action with an ankle injury. Sergio Garcia and Rickie Fowler shared second behind McIlroy. Garcia shot 70, while Fowler managed a 72.

Despite hoisting two Claret Jugs at St. Andrews, and boasting of swing improvements, Tiger Woods struggled again in a major championship. The three- time Open champion shot a 4-over 76, his worst round as a professional at St. Andrews.