Some superb approach play helped Australian Adam Scott take control of the Byron Nelson Championship in Irving, Texas midway through the third round.

Tied for the overnight lead with American Brett Wetterich, Scott birdied four of the first eight holes on the TPC at Las Colinas to move three strokes clear by the turn at 13 under par.

The 25-year-old struck approach shots to four feet at the second, eight feet at the fourth, three feet at the seventh and to within 10 feet of the flag at the eighth to stay on track for his fourth PGA Tour title.

Although he stumbled at the par-four ninth, pushing his drive right for his ball to bounce off a tree into water, he managed to reach the green in three before two-putting for a bogey-five.

Scott, a three-times winner on the PGA Tour, also earned an unofficial victory at last year's Nissan Open in Los Angeles when the rain-hit tournament was cut to 36 holes.

Wetterich, who shot a seven-birdie 64 in Friday's second round, offset a bogey at the first with a birdie at the third to share second place at 10 under after nine holes.

Level with Wetterich was South African Trevor Immelman, four under for the day after 11 holes, with American Omar Uresti a further two strokes back in fourth, after nine.

Former US PGA champion Jeff Sluman made the most significant move among the early starters on a sun-baked day, a six-under-par 64 lifting him into a share of the clubhouse lead at six-under 204.

Of the other big names, 1995 winner Ernie Els was at four under after 14 holes and level with 2003 champion Vijay Singh, after 16.