Second-ranked defending champion Rory McIlroy, with a chance to return to world No 1, lurked one stroke behind American co-leaders Gary Woodland and Trey Mullinax after Thursday's opening round of the CJ Cup.
Woodland, the 2019 US Open champion, and Mullinax, who notched his first PGA victory in July at the Barbasol Championship, each fired a six-under par 65 at Congaree Golf Club in Ridgeland, South Carolina.
McIlroy, who can overtake top-ranked Masters champion Scottie Scheffler with a victory, shot a bogey-free 66.
"I drove the ball well. I took advantage of the par-5s," McIlroy said. "If I can keep driving it like that over the next few days, I'll be in a good spot."
Woodland seeks his fifth PGA victory and first since claiming his only major title three years ago at Pebble Beach.
"I drove the golf ball well all day, saw some putts go in and that kind of freed up the ball-striking," Woodland said.
Mullinax was 7-under through 12 but took his lone bogey at 14 to stumble back.
"Played really well tee to green, hit a lot of really good golf shots, putted really well on the front," Mullinax said. "Ball-striking was really good. I was very pleased."
Four-time major winner McIlroy shared third with South Korean Kim Joo-hyung, Americans Aaron Wise, Kurt Kitayama and Wyndham Clark and Australian Cam Davis.
McIlroy made three birdie putts from about three feet and his longest came from just outside 12 feet at the par-3 fifth. He added another from just outside six feet at the par-5 12th.
"It's a golf course where you can hit driver a lot," McIlroy said. "The fairways are quite generous, but if you go off the fairways, you can get in some trouble."
In his first event of the new 2022-23 PGA Tour season after winning the FedEx Cup playoffs in August, the 33-year-old from Northern Ireland is chasing his 23rd career US PGA triumph and third of the year after taking the Canadian Open and Tour Championship.
'CARROTS' MOTIVATE MCILROY
McIlroy is also preparing for next month's DP World Tour Championship in Dubai as well as hoping to overtake Scheffler, who edged McIlroy at the Masters only to lose to him at the Tour Championship. McIlroy was last atop the rankings in July 2020.
"If I didn't have these two sort of carrots out in front of me, but had come off the season that I've had, it would be very easy to just take the rest of the year off and be like I'll see everyone in Hawaii in January," McIlroy said.
"But I still feel motivated and I think playing well motivates you even more also. There's definitely no lack of that."
Mullinax, 30, birdied four of the first six holes, his longest putt in the run from just outside 20 feet to birdie the par-4 sixth, and added a 26-foot birdie putt at the par-4 ninth to make the turn at 5-under.
He added a 23-foot birdie putt at the par-4 11th and reached the green in two at 12 to set up a tap-in birdie before missing a five-foot par putt at the par-3 14th.
Woodland, 38, opened with three consecutive birdies and added another from seven feet at the sixth before taking a bogey at the ninth. He made birdies at 11 and 12 and a bogey at 14 as well but closed with back-to-back birdies to share the lead.
"Playing from the fairway out here is a huge advantage and I was able to attack a little bit from there as well," Woodland said.