US TOUR: Former champion Zach Johnson rattled up four consecutive birdies in hot, blustery conditions en route to an early one-shot lead in yesterday's opening round of the Colonial Invitational in Fort Worth, Texas.

The 36-year-old American fired a flawless six-under-par 64 at Colonial Country Club where he won the 2010 title by three shots to claim his seventh victory on the PGA Tour

As temperatures topped 32 degrees, Johnson covered his front nine in a sizzling five-under 30 after launching his birdie run at the par-three 13th before ending the day a stroke in front of PGA Tour rookie Harris English.

Sergio Garcia saved par from greenside bunkers on his last two holes for an opening 66, finishing level with Americans Chris DiMarco and Tommy Gainey

Three more Americans – Ryan Moore, Daniel Summerhays and Roberto Castro – were a further stroke back on 67.

Johnson, who has not triumphed on the PGA Tour since his 2010 win at Colonial, set the tone for a memorable day with a 40-foot birdie putt on his opening hole, the par-four 10th.

He then sank putts from between 14 and 22 feet to birdie the 13th, 14th, 15th and 16th before reaching the turn in five under.

Though he picked up just one more shot, at the par-four third, as winds gusted up to 30 mph (48 kph), Johnson was delighted with his round.

“Today was great,” the 2007 Masters champion told reporters.

“I just hit some quality shots. Ive got zero complaints.”

In-form American Jason Dufner, winner of the Byron Nelson Championship on Sunday who is seeking a third PGA Tour victory in just four weeks, was four under par after 14 holes, while Tom Gillis was five under par coming up the last.

American David Toms, who won last year’ s Colonial Invitational by one shot, launched his title defence with a 74.