LAS VEGAS -- Stuart Appleby made three straight birdies on the back nine Saturday and shot a 6-under 66 to take a one-shot lead after the fourth round of the Las Vegas Invitational.
Appleby, chasing his first tour win since 1999, is at 28-under 259 heading into Sunday's final round of the 90-hole tournament.
Steve Flesch, who started the day in a tie for the lead with Scott Verplank, shot 68 and is a stroke behind Appleby at 260.
Scott McCarron, who has never won the tournament despite contending several times, is three shots back after a 5-under 67. Robert Allenby (66) is four shots behind Appleby.
Scores in the low 60s were common through the first three rounds. Things got back to normal in the fourth round with tougher pin placements at the TPC at Summerlin course.
That didn't slow down Appleby, who consistently hit big drives that found the middle of the fairway and left him with short irons to the green.
He had nine birdies and three bogeys and kept the lead by getting up and down for par on the par-3 17th. His tee shot went left of the green, the ball coming to rest a couple of yards short of the water. From there, he hit a lob wedge to 3 feet and made the putt.
"I pulled it left and it popped down the slope," Appleby said of his tee shot. "I got away with it."
Flesch, who opened the tournament with a 62 on Wednesday, had four birdies and no bogeys Saturday.
"A four-birdies, no-bogey round is pretty mundane on this course," Flesch said. "Tomorrow I want to convert the opportunities I had today."
Verplank was at 26 under and within two shots of Appleby going to the par-5 16th, but took a triple-bogey 8 after hitting two shots in the water. He also bogeyed 18 and finished with a 73.
Appleby finished second here last year, a shot behind Phil Tataurangi. He came into this week with second place finishes in his last two tournaments, including last week at the American Express Championship.
"I like the way I'm playing and I'd like to get it 6 or 8 under tomorrow," he said.
Flesch, a winner at New Orleans in April, has led or been near the top of the leaderboard all week.
"I know I haven't played my best golf yet," he said. "I know I have it in me to run the table again."