Tommy Fleetwood moved into contention to succeed Ryder Cup partner Francesco Molinari as Open champion as Tiger Woods tried to avoid an early exit at Royal Portrush.
Fleetwood outscored Woods by 10 shots in the first round and took advantage of ideal conditions for the early starters on Friday to card a superb 67 and set the clubhouse target on seven under par.
World number one Brooks Koepka, who is seeking a fifth major victory in his last 10 starts, was ominously poised on five under following a 69, with South Africa's Erik van Rooyen on four under and England's Tyrrell Hatton a stroke further back after an eventful 71.
Overnight leader JB Holmes had carded five birdies and a bogey in his first 13 holes to remain out in front on nine under par.
Fleetwood was expected to contend for one of the game's biggest prizes this year after his consistent displays in 2018, the Ryder Cup star finishing 17th in the Masters, second in the US Open – after a record-equalling 63 in the final round – 12th in the Open and 35th in the US PGA.
However, so far this season his best result is a tie for 36th at Augusta National and the 28-year-old also failed to convert good chances to win the Arnold Palmer Invitational and Players Championship earlier in the year.
A bogey on the first was quickly cancelled out by a birdie on the par-five second and Fleetwood also picked up shots on the fifth, 12th, 13th and 15th before bouncing back from a bogey on the 16th to birdie the last.
"Yesterday I felt like it was a lot more stress-free, today I made two or three really good par saves but I am happy with the challenge," Fleetwood said. "It's not going to be all-singing and dancing in majors and I was up to the test.
"Overall it's two really good rounds of golf to start."
Woods admitted he had a "hard time moving" during his warm up for the first
round and carded just one birdie in a seven-over 78, his highest opening round in 21 Open appearances by three shots.
The 43-year-old, who underwent spinal fusion surgery in April 2017 and won his 15th major title in the Masters two years later, faced a tall order to avoid missing the cut but made the ideal start with a birdie from 30 feet on the first.
Woods also birdied the sixth but will have been furious to drop a shot on the par-five seventh, one of the easiest holes on the course, after pulling his approach left of the green.
A birdie on the 10th took Woods back to five over par, four shots outside the projected cut.