Matthew Fitzpatrick turned in 31 to hit the front on day two of the WGC-FedEx St. Jude Invitational at TPC Southwind.
The Englishman started the second round five shots off the lead as the event made its first appearance in Memphis but he made five birdies on the front nine to get to seven under.
Overnight leader Jon Rahm made a slow start as he dropped to six under alongside Americans Patrick Cantlay and Andrew Putnam, Japan's Hideki Matsuyama and Australian Cameron Smith.
Fitzpatrick is a five time European Tour winner with a victory in every full season since he got his card at the 2014 Qualifying School, but his best result so far in a World Golf Championships event is a tie for seventh at the WGC-HSBC Champions in his rookie season.
He made a stunning start with four birdies and most of that was due to some brilliant iron play.
He holed from 26 feet on the second but his approaches to the first and third were both to eight feet, while he put his tee shot on the par three fourth to nine.
The 24 year old very briefly had a share of the lead when Rahm bogeyed the par five third after nearly finding the water but he made a bogey of his own after finding sand off the tee at the par three eighth.
Rahm then missed the green at the fourth to make it back to back bogeys and another brilliant approach to seven feet from Fitzpatrick at the ninth edged him ahead.
Putnam was two under for his round through seven holes, while Cantlay, Matsuyama and Smith had each picked up a single shot in the early stages.
Bryson DeChambeau, Shugo Imahira and Nate Lashley were at five under, a shot clear of a group containing Tyrrell Hatton, Billy Horschel, Ian Poulter and World Number One Brooks Koepka.
