Memphis - Harris English, an American in only his second season on the PGA Tour, matched his low round of the year with a six-under par 64 on Friday to seize a two-stroke lead at the St. Jude Classic.
English, whose other 64 came in the first round at last month's Byron Nelson Championship, stood on 10-under 130 for 36 holes with compatriot Shawn Stefani second on 132 after a firing a second-round 65.
"I'm still getting comfortable out here, just trying to get in the hunt of a golf tournament every time," English said. "I've worked very hard the last couple weeks and couple months to get in this position."
English, seeking his first PGA triumph, opened with three birdies in a row and holed out from 175 yards in the fairway for eagle at the par-4 fifth.
"I was playing a little short of it because that green goes front to back pretty good," English said. "It landed about 10, 12 feet short and kicked right and rolled right in."
The 23-year-old former University of Georgia standout with three top-10 finishes this season, added birdie putts at 15, from 15 feet, and 16, from nine feet, before closing with his lone bogey.
"When I get in that kind of situation, everything is pretty much going my way and I'm very much in control of my ball," English said. "I'm really trying to birdie every hole."
Stefani had a bogey-free round with back-to-back birdies at the par-5 third and par-3 fourth as well as the par-3 eighth and par-4 ninth and a final birdie at the par-5 16th.
Americans Scott Stallings and Paul Haley shared third on 135, five strokes off the lead. Davis Love was in an all-American group on 136 that also included Glen Day, Justin Hicks, Nicholas Thompson and Doug LaBelle.
Defending champion Dustin Johnson, in his first event since a back injury forced him out of the Players Championship last month, fired a 70 to stand in a pack on 137.
Phil Mickelson, a five-time US Open runner-up who will try again to finally claim the long-sought crown next week at Merion, fired a 67 to stand in a group on 138, much happier than after his opening-round 71.
"I let a number of shots slide (Thursday)," Mickelson said. "I made a couple of dumb mistakes and I think that's why I enjoy the competing element before a big event like the US Open next week.
"And I'm not selling myself out this week. I feel like if I play better than I did today, I've got a low round in me."
Leading scores on Friday after the second round of the $5.7 million PGA Tour St. Jude Classic (USA unless noted, par-70):
130 - Harris English 66-64
132 - Shawn Stefani 67-65
135 - Paul Haley 67-68, Scott Stallings 67-68
136 - Davis Love 66-70, Glen Day 66-70, Justin Hicks 67-69, Doug LaBelle 70-66, Nicholas Thompson 67-69
137 - Jason Bohn 67-70, Ben Crane 69-68, Dustin Johnson 67-70, Stuart Appleby (AUS) 66-71, Luke Guthrie 70-67, Eric Meierdierks 68-69, Chez Reavie 69-68, Roberto Castro 68-69, Bob Estes 68-69, Boo Weekley 68-69, Ian Poulter (ENG) 69-68, Camilo Villegas (VEN) 69-68
138 - Martin Flores 66-72, Scott Brown 69-69, Rory Sabbatini (RSA) 69-69, Peter Hanson (SWE) 67-71, Patrick Reed 69-69, John Rollins 67-71, Billy Mayfair 68-70, Russell Knox (SCO) 70-68, DJ Trahan 69-69, Charles Howell 71-67, Phil Mickelson 71-67, David Toms 67-71, Stephen Ames (CAN) 70-68, Robert Karlsson (SWE) 69-69, Jim Herman 69-69