DeChambeau, who finished runner-up at last month’s PGA Championship, carded a one-under-par 69 that left him four under at Pinehurst No 2 where Detry (67) boosted his hopes of becoming the first Belgian major title winner.
“I’m excited for the game that I have right now,” DeChambeau said. “I feel pretty confident and ready to get after it this weekend.”
Patrick Cantlay, who shared the overnight lead with McIlroy, went out late and mixed a birdie with a double-bogey to reach the turn in one over 36 that left him at four under.
Cantlay ran into trouble at the par-four eighth where his approach shot rolled off the green before he failed to get his next two chips to stay on the putting surface.
Swede Ludvig Aberg, one under through eight holes, was the on-course leader at five under while Frenchman Matthieu Pavon, one under through four holes, was among a group one back.
McIlroy, seeking an elusive fifth major, was unable to build on his bogey-free opening round as he returned an adventurous 72 that featured near-misses and stunning par-saves, including at the par-three 17th where he holed a putt from off the green.
“Overall, I felt like I did a pretty good job at keeping some of the mistakes off the scorecard,” said McIlroy. “I wish I had converted a couple more of the chances.”
The Northern Irishman was at three under, one shot clear of former Masters champion Hideki Matsuyama (66).
Mixed start
After a roller-coaster start, DeChambeau got into the mix with back-to-back birdies at 12 and 13 before a bogey at 15 where his tee shot found a bunker.
But DeChambeau, the 2020 US Open champion and one of 12 LIV Golf players in the 156-player field, capped his round in style as he tapped in for birdie after leaving his approach shot 15 inches from the cup.
Detry mastered Pinehurst No 2’s notoriously tricky dome-shaped greens as he made nine one-putts on the day, the last at his 12th hole where he rolled in a 22-footer.
“I feel like this week, you make a par, you gain on the field, keep moving on,” said Detry. “I always seem to do better that way. It puts a little bit less pressure on my putting. When I have a birdie chance, it’s like a bonus.”
Masters champion Scheffler, who entered the year’s third major as the clear favourite, was unable to take advantage of quality iron shots as he carded a 74 that left him at five over and sitting right on the projected cut line.
“This golf course can be unpredictable at times, and maybe it got the better of me the last couple days,” said Scheffler.
Tiger Woods, competing in only his fourth event of the year, also went out with the late starters and was five over on the week with nine holes left in his second round and also in danger of missing the cut.
The top 60 players and ties will make the cut and play the final two rounds over the weekend.
Among players outside the projected cut line were world No 5 Viktor Hovland, 2016 US Open champion Dustin Johnson and Phil Mickelson, who this week was looking to complete the career Grand Slam of golf’s four majors.