The South African's effortless 6-under par round leaves him one ahead of Jordan Spieth and Brian Harman going into Friday.
Oosthuizen Takes Early Initiative At The Open
Louis Oosthuizen shot an effortless, bogey-free round of 64 at the first day of the 149th Open Championship, leaving him one shot clear of American Jordan Spieth.
The South African was paired with 2019 champion Shane Lowry and world number two Jon Rahm and outplayed the pair of them on his way to a serene six birdies and 12 pars.
The performance follows Oosthuizen's second place finish at the US Open last month and the 2010 Open champion will be looking to end a run of second place finishes at Majors.
Related: Open Championship Full Leaderboard
The early starters had the better of the weather - with lighter winds and brighter skies - and the majority of the overnight top 10 started before noon local time.
Jordan Spieth's excellent round of 65 featured a string of four consecutive birdies on his front nine and leaves the 2017 champion just one shot behind the lead.
Left-hander Brian Harman joined Spieth on 5-under par with an equally punchy round of golf that included three birdies on his first three holes.
Elsewhere, Dylan Frittelli, Mackenzie Hughes and Stewart Cink all finished 4-under par after starting in the first half of the draw.
Webb Simpson and Benjamin Herbert's rounds of 66 were the best from the afternoon groups, whilst Tommy Fleetwood (-3) and Collin Morikawa (-3) were similarly impressive as conditions worsened in the afternoon.
Related: “Painful When Bryson Says Something That Stupid”: Cobra Hits Back At Bryson
Andy Sullivan was the early clubhouse leader after teeing off at 6:35am BST alongside Richard Bland and Marcus Armitage.
Defending champion Shane Lowry posted a disappointing 1-over par 71, but arguably provided the shot of the day with this wedge out of the deep rough.
All in all, 32 players finished under par on the first day at Royal St. George's on an entertaining day as The Open retuned for the first time since 2019.
Elsewhere on a busy day in golf, Bryson Dechambeau (+1) claimed his driver "sucked", Cobra representatives said it's, "painful when Bryson says something that stupid", and Garcia (-2) and Fitzpatrick (+1) had traffic issues getting to the course.
