America's Jackson Suber will take a one-shot lead into the second round of the 2026 Open.
The 26-year-old went round Royal Birkdale Golf Club in Southport in five-under 65 on Thursday.
He leads England's Dan Brown and South Korea's Sungjae Im by one stroke.
A group of nine players, including Robert MacIntyre, Cameron Young, Thomas Detry and Bryson DeChambeau are a further stroke adrift.
World number one and reigning Open champion Scottie Scheffler began his quest to add a second Claret Jug to his resume with a 68.
Masters champion Rory McIlroy faces a battle to make the cut, with the Northern Irishman seven strokes adrift of Suber.
England's Tommy Fleetwood and Tyrrell Hatton ended the day on one under alongside their Ryder Cup teammate Jon Rahm.
England's Matthew Baldwin, a member of Royal Birkdale, had the honour of hitting the opening tee shot at the 154th Open.
Baldwin earned his spot in the 156-man field by advancing through final qualifying last month.
The 40-year-old puffed out his cheeks before sending his tee shot down the right side of the fairway.
He made a steady par and has backed it up with two more pars at the second and third.
