England's Matt Fitzpatrick shot a second-round 64 to take a two-stroke lead in the WGC-FedEx St Jude Invitational in Memphis.
The Yorkshireman's advantage would have been less had Bill Horschel not bogeyed his final hole to drop into a tie for second place.
Sheffield-born Fitzpatrick, a five-time winner on the European Tour who finished second in March’s Arnold Palmer Invitational on the PGA Tour, got his round off to a flier with four successive birdies.
Key to that was the quality of his iron play, and although he dropped a shot at the par-three eighth, he had two more birdies coming home to lift him to nine-under.
He looked like being caught by Horschel, who started on the back nine with two birdies, before a bogey, an eagle and two further birdies put him within one of the lead until he dropped his second shot of the day at the par-four ninth to card a 66.
Northern Ireland’s Rory McIlroy improved his prospects with an encouraging bogey-free 67 to sit five shots behind Fitzpatrick on four-under.
Overnight leader Jon Rahm, after his brilliant opening 62, salvaged his round with a late flourish after four bogeys in 15 holes.
Back-to-back birdies at 16 and 17, added to the earlier one at the 13th, saw him sign for a one-over 71 but still remain in contention at seven under along with Horschel, fellow American Patrick Cantlay and Australian Cameron Smith.
English duo Ian Poulter and Justin Rose and four-time major winner Brooks Koepka are at five-under.