Alex Fitzpatrick fired a brilliant seven-under-par 64 to grab a one-shot lead going into the final round of the Truist Championship at Quail Hollow.

The 27-year-old, younger sibling of ex-US Open winner Matt Fitzpatrick, delivered a masterful performance with eight birdies, reaching 14 under par and positioning himself for a first solo PGA Tour victory.

Fitzpatrick holds a narrow advantage over Norway's Kristoffer Reitan, who matched his 64.

Just two weeks ago, the Fitzpatrick brothers claimed the Zurich Classic of New Orleans team title, earning Alex a two-year PGA Tour exemption; he sits 120th in the world rankings.

World No. 2 Rory McIlroy, a four-time champion here, endured a tough Saturday with a four-over 75 that knocked him from the top of the board.

Teed off two strokes behind the leader, Fitzpatrick charged ahead thanks to five birdies on the front side.

He weathered a bogey at the 16th but bounced back with an eight-foot birdie putt at the par-three 17th to reclaim his slim lead.

"One area where I excelled today was fully embracing the moment," Fitzpatrick noted.

"The crowd support was incredible out there.

"I'd love nothing more than to win - I'd trade a lot for it. But if it doesn't come today, I trust it'll happen eventually. As long as I enjoy the process, that's what matters."

Meanwhile, McIlroy's push for a follow-up win after his recent Masters success unraveled during a challenging afternoon in Charlotte for the Northern Irish star.

Plagued by six bogeys, he tumbled to one under par, now 13 strokes off the pace.

American Cameron Young posted the day's best score, an electric eight-under 63, landing solo third at 12 under. The recent Cadillac Championship winner notched his lone bogey at 18 after a errant drive.

South Korea's Sungjae Im, who led at the midpoint, stands at 10 under following a 70, joined by Denmark's Nicolai Hojgaard after his strong 67.

England's Tommy Fleetwood stays in the mix with a 70, tied for sixth at nine under alongside two-time major champion Justin Thomas.