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HOUSTON (Reuters) - Australian Matt Jones fired a course-record 66 at the new Oaks Course at TPC San Antonio for a one-stroke lead after the opening round of the Texas Open on Thursday.

The 30-year-old from Sydney, who has posted four top-10 finishes on the U.S. PGA Tour this season, sank a six-foot putt for eagle at the par-five 14th hole to help him reach six under par for the day after starting with a double-bogey.

Jones made the turn at even-par before mounting a charge.

"I made about a 30-footer for par on 11 which kind of kept me going and from there on we had (four) birdies and an eagle," said Jones, who shot a sizzling six-under 30 on the back nine.

Jones said he felt his game was picking up after putting in some work with his coach.

"I wasn't playing the greatest but my coach is in from Australia," he said. "I have a lot of confidence in him. We've been working hard this week and will probably go out and do some more work."

World number seven Ernie Els, the top-ranked player in the field, had a birdie, two bogeys and a double-bogey before he electrified the gallery at the 14th when his second shot from 293 yards out of the left rough settled 18 inches from the cup for an eagle tap-in. He shot even-par 72.

"The eagle helped me obviously on 14," said Els, who has won twice this season. "I hit a very nice second shot there and then the birdie on 17 also helped. Yeah, back to even par but I feel like it could have been a low one out there."

Zach Johnson, the 2007 U.S. Masters champion who was trying to emulate Arnold Palmer by winning the event for a third year in a row, failed to recover from a poor start.

Johnson had five bogeys on the front nine and compounded his woes with a quadruple-bogey at the par-three 13th on his way to registering an eight-over-par 80.

"All aspects. Very poor," summed up Johnson.

(Writing by Larry Fine in New York, Editing by Frank Pingue)