Los Angeles - Australian Marc Leishman followed up his career-best 61 with a five-under-par 66 on Friday to stay atop the Byron Nelson leaderboard with a tournament-record 36-hole score of 15-under par 127.
Leishman broke the 36-hole record of 12-under 128 achieved on six prior occasions at the tournament's former home of TPC Four Seasons, including twice by Tiger Woods and most recently by Jason Kokrak last year.
Leishman fired six birdies with one bogey on the par-71 Trinity Forest course south of downtown Dallas and will take a one-shot lead over US PGA Tour rookie Aaron Wise into the weekend.
Wise jumped up the leaderboard with a 63 for 128, edging ahead of veteran Brian Gay who fired 10 birdies in a nine-under par 62 for 129.
Leishman was delighted to deliver another solid round at Trinity Forest, the first-time host of the tournament held for 35 years in suburban Irving.
"When you shoot a really low one like I did yesterday it's hard to back it up," said Leishman, who had a 15-under-par total of 127 and a two-shot lead with the afternoon starters still on the course.
Leishman teed off on 10 and kick-started his round with a 56-foot birdie putt at the par-three 12th.
"My speed has been really great," said Leishman after enjoying another stellar day on the greens. "Last week at The Players I hit a lot of really good putts that lipped out, and this week they're going in.
"Some weeks you read them really well, and some weeks you're not sure if a 10-footer is slightly uphill or downhill, and that affects your speed and line and everything."
Leishman tapped in for birdie at 14 before a bogey from a greenside bunker at 15.
Coming in, he birdied four of five holes from the first through the fifth, and said he was enjoying the challenge of the links-style Trinity Forest course.
"I enjoy this type of golf, it reminds me of back in Australia," Leishman said. "I like how the ball is running out in the fairways.
"I'm reading the greens well and hitting the ball well. Hopefully I can keep that up over the last two days," added the 34-year-old Aussie, who claimed the most recent of his three US tour titles at the 2017 BMW Championship.
Wise made four birdies in his last seven holes to put himself in position to challenge for a first PGA Tour title.
"First time I've been in the hunt with something to look back to," said Wise, who charged late but came up short at the Wells Fargo this month. "I did great two weeks ago and it's just get it going and feeling good about the game. (I'm) excited to go tee up tomorrow."
Leading second-round scores on Friday in the US PGA Tour Byron Nelson tournament in Dallas, Texas (USA unless noted, par-71):
127 Marc Leishman (AUS) 61-66
128 - Aaron Wise 65-63
129 - Brian Gay 67-62
131 - Jimmy Walker 64-67, Eric Axley 66-65, Kevin Na 66-65
132 - Martin Piller 69-63, Adam Scott (AUS) 67-65, Matt Jones (AUS) 67-65, Kevin Tway 67-65, Vaughn Taylor 68-64
133 - JJ Spaun 64-69, Keith Mitchell 65-68
134 - Mark Wilson 68-66, Patrick Rodgers 67-67, Shawn Stefani 68-66, Abraham Ancer (MEX) 65-69, Branden Grace (RSA) 66-68, Hudson Swafford 70- 64
135 - Ryan Blaum 66-69, Anirban Lahiri (IND) 68-67, Peter Malnati 69-66, Jordan Spieth 69-66, Peter Uihlein 65-70, Robert Garrigus 66-69, Troy Merritt 67-68, Joel Dahmen 67-68, Nicholas Lindheim 66-69, Hideki Matsuyama (JPN) 72-63, Johnson Wagner 67-68