Scheffler had looked set to tear up the classic Lancashire links course on Thursday morning as one of the early starters cashing in a cloudless, windless conditions, birdieing four of the first six holes to be outright early leader.
But with the breeze gusting up, Birkdale eventually bared its teeth to the extent the 30-year-old was pegged back to a two-under 68 -- good enough to earn him an early top-10 position but not where he'd hoped after his spectacular opening.
By mid-afternoon, Scheffler, winner at Royal Portrush last year, was two off the clubhouse lead, held by South Korea's Sungjae Im and Englishman Dan Brown, who both flourished late in their morning rounds as they shot four-under 66s.
Scheffler was a shot behind half-a-dozen players on three-under 67, including his playing partner luminary Bryson De Chambeau, former winner Francesco Molinari, Scottish Ryder Cup star Robert MacIntyre, and fellow Americans Ryan Gerard and Alex Smalley.
Smalley had been in a position to grab the outright lead as he led on five-under going to the 18th, only to drive out-of-bounds and end up with a double-bogey six.
Seeking to become the Open's first back-to-back winner since Padraig Harrington in 2008, Scheffler began immaculately, holing from 14ft at the second, seven feet at the third, five feet at the fifth, before a whopping 43-footer at the sixth put him out on his own.
From there, it got more diffficult. "There were really only a few shots I hit offline today," he sighed. "I didn't get up-and-down on seven and then missed the fairway on 10 where I'm in a pot bunker, and then on 17, I end up in 'that' spot."
'That' spot turned out to be embedded in thick grass, which eventually cost him a bogey. "It looked like somebody had potentially stepped on it, but nobody would fess up," he shrugged. "Apparently nobody did.
"I got off to a hot start but wasn't able to make as many birdies as I would have hoped to down the stretch. I played the par-fives over par.I felt like I could have gotten a little bit more out of the round, but if I continue to do what I did today with the ball-striking I'll be in a good spot as the week goes on."
Im recorded four birdies in the last nine holes, while Brown made seven birdies on his final 11-hole stretch.
While 37 players were in under-par red figures after the morning wave, none of the early Australian contenders were able to break par, with Min Woo Lee needing a fine 16-foot par save at the last to finish level par.
Jason Day ignited his round with a 30-foot birdie on the fifth hole, but his round ended up ebbing away as he finished with a three-over 73.
Travis Smyth, inspired by having played alongside Scheffler in a practice round on the eve of the tournament, ended with a one-over 71, while former champion Cam Smith was three over with a couple to play.
Playing alongside Scheffler seemed to inspire two-time major winner DeChambeau, who had five birdies offset by a couple of bogeys in his promising 67.
The recent heatwave and lack of rain had given Birkdale a very different brown-tinged look, with the fairways running lightning fast compared to its last edition on the British Open rota back in 2017 when American Jordan Spieth lifted the Claret Jug.
English sports fans needed a bit of cheer following their World Cup soccer misery the night before against Argentina, and they found an unlikely hero in co-leader Brown, a cigarette-puffing 40-year-old who had seven birdies in his uneven round. He had also led after the opening day at Royal Troon in 2024.
Local Southport hero Tommy Fleetwood, cheered to the rafters on every hole, shot a 69, while another luminary to impress early on was Jon Rahm, who also finished at one under.
