Scottie Scheffler lived up to his billing as the pre-tournament favourite at The Open Championship as he jumped ahead of Matt Fitzpatrick to grab the halfway lead at Royal Portrush.
Scheffler, chasing a second major win and fourth PGA Tour title of the season, made the best of the changing weather conditions to card a superb 64 to leave him at eight under.
The world number one finished with a flourish in Northern Ireland, scoring two birdies on two of his last three holes to edge ahead of Fitzpatrick, who fired a five-under 66.
Scheffler holds a one-shot lead over the Briton, with 2023 champion Brian Harman two back in tied-third alongside Haotong Li, with the pair impressing on the second day.
Ryder Cup team-mates Tyrrell Hatton and Bob MacIntyre are in the group in tied-fifth that includes Rasmus Hojgaard, Scottish Open champion Chris Gotterup and Harris English.
Rory McIlroy remains in contention and heads into the weekend on three under alongside Keegan Bradley, with defending champion Xander Schauffele one shot back.
Scheffler entered the second day one shot off the pace, and started as he meant to go on with a birdie on the first hole, which was followed by three more from the fifth.
But Fitzpatrick, out earlier than the American, was more than playing his part after a stretch of four birdies in his opening seven holes, and he did not stop there.
He was the first player to reach 10 under after four birdies from the 10th, though a missed putt on 14 cost him a shot before a three-foot birdie putt on the 17th hole lipped out.
Scheffler, however, took advantage of the improving conditions later in the day, pulling level with Fitzpatrick after carding birdies on both par-threes on the back nine.
He took the outright advantage with a 15-foot birdie at the par-four 17th but left an effort to double his lead short at the last, but was able to save par to stay out on top.
Scheffler's score was his lowest in a major as he aims to become the second player after Tiger Woods to be crowned The Open champion as the current world number one.
It was, however, a day to forget for 2019 winner Shane Lowry, who received a two-shot penalty after his ball was adjudged to have moved while he was taking a practice swing.
He accepted the penalty by the R&A, which left him level par for the championship and just inside the cut mark of one over.
