HUMBLE, Texas -- Stuart Appleby thinks he has 10, maybe 15 years left on the PGA TOUR. He's determined to make the most of them.

The 34-year-old Appleby shot a 6-under 66 on The Tournament Course at Redstone Golf Club on Thursday to take the first-round lead in the Shell Houston Open.

"I'm trying to play well all the time," Appleby said. "I think that's an addictive thing you want to get into and you keep going and keep playing until it gets out of tune."

The Australian teed off early and took advantage of calm conditions on the new course, the event's third venue in four years. The Rees Jones-designed layout opened in August 2005 and most of the players are getting their first look at it this week.

Appleby said the course would yield low scores if the wind stayed down - and it did throughout his round.

"Conditions were quite easy," Appleby said. "There was definitely a 6-under score to be had out there by somebody and I was fortunate."

The breeze picked up later in the day, though, and the course toughened up.

"The wind can kind of mess with you a little bit," said John Daly, who shot a 69 in the afternoon. "It can change on your backswing."

Appleby said his round wasn't "clean and perfect," but a couple of "bonus" shots led to the sparkling score.

He sank a 25-foot birdie putt on the sixth and another one on No. 11. He hit a bad approach to the par-5 13th for his only bogey, then chipped in on No. 17 and made a downhill 20-foot birdie putt on the 18th.

"I hit it good enough to give myself opportunities," he said. "Could have been better, but could have also not chipped in and made some other stuff."

Appleby won the Shell Houston Open in 1999, when it was played at the TPC The Woodlands. But outside of Kapalua, where he's won the season-opening Mercedes Championships three straight years, Appleby has won only the 2003 Las Vegas Invitational since 2000.

His age is one number above his world golf ranking. But he has a plan to climb into the top 10, borrowing from both Tiger Woods and Phil Mickelson.

"Tiger always says he's trying to get better. That's the attitude you've got to have," Appleby said. "I think Mickelson has done a very comprehensive look at his game and learned from mistakes he's made. He's coming up with all sorts of ideas to do it.

"You always have to have a very open mind about what you need to do."

Jerry Smith and D.A. Points also benefitted from early tee times and shot 67s.

Smith, who turns 42 on Monday, is back on the PGA TOUR for the first time since 2002. He finished sixth on the Nationwide Tour money list last year, but he's missed three cuts in eight starts in 2006.

He's as surprised as anyone by his opening round.

"I wasn't comfortable last night," Smith said. "I think it's going to be a challenge for me all week. I don't try to deny anything, but maybe my game will start feeling a little better as the week goes along."

Australia's Aaron Baddeley, coming off his first PGA TOUR win last week at Hilton Head, was two strokes back after a 68.

Baddeley said the confidence he gained from the victory has carried over to this week.

"It's been good just knowing I've won out here, and when I do play well, (knowing) I can go ahead and finish and win," he said.

Fellow Aussie Stephen Leaney, Brent Geiberger and Charles Warren also shot 68s.

Two-time defending champion Vijay Singh was part of a group three shots back after 69s. Singh birdied all four par-5s, but bogeyed the 18th after hitting his tee shot into the fairway bunker.

Singh is the only one of golf's Big Five playing this week. Woods, Mickelson, Retief Goosen and Ernie Els are skipping the event.

Divots: David Toms, who worked with Jones on the course's design, shot a 71. ... Appleby is one of five Shell Houston Open champions from Australia. Robert Allenby, David Graham, Bruce Crampton and Bruce Devlin also won in Houston. ... Darren Clarke shot a 68, then withdrew and flew home to England to be with his cancer-stricken wife, Heather. Tournament organizers said Clarke dropped out to go home and "discuss further treatment with Heather and her doctors." Clarke's wife was diagnosed with breast cancer in 2002 and it has spread throughout her body.

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