Collin Morikawa showed no sign of inexperience when surging into the lead on his British Open debut at nine under par after a second round score of 64 on Friday.
The American is making his first appearance at the Open Championship and played for the first time on British soil last week at the Scottish Open where he finished in a tie for 71st.
However, the 24-year-old has already shown an ability to raise his game for the big occasion during his short career and he did so again with a round of six under at Royal St. George's.
In just seven previous major appearances, Morikawa has finished in the top-10 three times, including victory at last year's US PGA championship.
The last debutant to win on his Open debut was Ben Curtis in 2003, also at Royal St George's.
But while Curtis was a rank outsider who never matched the heights of his golden week in Sandwich, Morikawa is already ranked fourth in the world.
Starting out on Friday at three under, Morikawa picked up two shots in the first seven holes before hitting his stride around the turn.
Birdies at eight, nine, 11, 12 and 14 briefly took him to 10 under before he dropped his only shot of the day at the par-four 15th.
Another birdie putt on the 18th hit the lip of the cut and stayed out, but Morikawa was still three shots in front of overnight leader Louis Oosthuizen and another South African Daniel van Tonder.
Van Tonder also made the most of Friday's pleasant early morning conditions under blue skies and a soft wind to post a four under par round of 66.
Tony Finau, the only player to finish in the top 10 at both the two previous British Opens in 2018 and 2019, also made his move with a 66 to get to four under.
Meanwhile, Rory McIlroy is in danger of missing the cut for a second consecutive Open Championship.
Resuming at level par, the Northern Irishman bogeyed the opening two holes.
The four-time major champion recovered from that poor start with birdies at four and nine, but made the turn just one shot better than the projected cut line of one over.
Phil Mickelson is set to miss the weekend after his nightmare 10 over par round of 80 on Thursday.
Nevertheless, the US PGA champion was making a better fist of his second round at level par for the day through 12 holes.