Leishman shot a 10-under-par 61 to hold a three-stroke advantage after the opening round at Trinity Forest in Dallas.
The 34-year-old Victorian, a three-time winner on the PGA Tour, started with an eagle on the par-5 1st hole and never looked back, claiming another eagle at the 14th to go with six birdies.
Leishman, who left himself a four-foot putt on the 18th for his 61, said the thought of shooting 59 barely crossed his mind.
“I didn’t think about that,” he said. “I didn’t want to let myself get ahead of myself which was good.
“Sixty-one. I’ll take that.”
Leishman had previously posted four scores of 62, including his opening round in last year’s BMW Championship which he went on to win by five shots.
The World No.16 didn’t miss a fairway for just the third time during his career.
“That’s the key around here,” he said. “The fairways are generous but if you are off them you are in trouble.”
Leishman reads the 18th green during the first round of the AT&T Byron Nelson. PHOTO: Tom Pennington/Getty Images.
Fellow Australian Adam Scott, desperate to improve his No.65 world ranking in a bid to earn automatic entry into next month’s US Open, fired a four-under-par 67.
Scott’s round was matched by Matt Jones and Cameron Percy.
Leishman made the turn in four-under before reeling off three successive birdies on the 10th, 11th and 12th holes.
He hit his second shot on the par-5 14th to 13 feet and drained the putt for eagle before sinking a birdie putt on the par-3 17th.
“To play like I did today, I didn’t hit it in too many bad spots so I think that makes it a lot easier,” Leishman said.
“I was hitting the right side of the fairways (with) good iron play and I obviously had a hot putter as well,” Leishman said.
“It’s a pretty good combination for a good score.”
Leishman was in a tie for 63rd at last week’s Players Championship and he was in contention after two rounds of last month’s Masters Tournament before finishing ninth, seven shots behind the winner Patrick Reed.
Americans JJ Spaun and Jimmy Walker are Leishman’s nearest challengers, each carding seven-under-par 64.
– Warwick Barr, Australian Associated Press
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