Zach Johnson completed his first round to lead the field of the 2013 British Open. Johnson currently sits in first place with a 5-under 66, one stroke in front of his nearest competition.
56-year-old Mark O'Meara sits in second place with 4-under through his first 11 holes. He is tied there with Rafael Cabrera-Bello, who wrapped up his first round earlier in the morning.
Brandt Snedeker, who was also among Thursday's early tee times, made a push down the stretch to finish 3-under, currently good for a fourth-place tie. Through 14 holes, Snedeker sat at 1-under, but rallied to close his first round at 68.
Phil Mickelson finished his first round at 2-under, making four birdies and two bogeys.
Check out the complete leaderboard at The Open Championship's official site.