Padraig Harrington was unable to keep pace with defending champion Adam Scott in early stages of the Houston Open today.
Scott fired a nine-under-par 63 to surge into a three-stroke lead while Harrington, fifth in New Orleans last weekend, just managed to break par with a one-under 71.
Scott birdied six holes on his front nine after starting his round at the 10th hole and added three more birdies in a bogey-free round at Redstone Golf Club's Tournament Course.
Steve Stricker, who birdied four holes on his second nine to post a 66, was second. Grouped at five-under-par 67 were 2006 US Open champion Geoff Ogilvy, Briny Baird and Dean Wilson, who dropped from a tie for second with a bogey at the 18th.
Justin Leonard and Brett Quigley were a further stroke back.
Among other notables, Jesper Parnevik posted a three-under 69 while twice Houston winner Stuart Appleby registered 70.
John Daly failed to take advantage of good scoring conditions, posting a six-over-par 78 on a layout set up to mimic features of Augusta National, site of next week's first grand slam tournament of the year, the US Masters.
Late starters in the field included world number two Phil Mickelson, seventh-ranked K.J. Choi and twice Masters winner Jose Maria Olazabal.
Another of Thursday's late starters was Davis Love III, who must win the tournament to join next week's Masters field and continue his streak of playing in 70 successive majors dating back to the 1990 British Open.
