US TOUR: GEOFF OGILVY'S closest challengers were left demoralised and trailing in his wake after the Australian surged six strokes ahead of the field in the Mercedes-Benz Championship third round on Saturday.

Although relatively benign conditions at the Kapalua Resort led to a rash of low scores in the PGA Tour's opening event of the season, Ogilvy was among them as he fired a sparkling, eight-under-par 65.

"I was looking at the leaderboards on the back nine but I never saw Geoff's section, so I didn't know where he was," Justin Leonard said after climbing into a tie for second with an eight-birdie 65.

"And then when I got to 18, I saw he was at 19 under. So it was a little deflating, to say the least.

"Hats off to him," added Leonard.

Tour veteran Kenny Perry returned a flawless 68 to end a sun-baked day of light breezes seven shots behind Ogilvy.

"It's definitely his tournament, so we all are going to be fighting for second it looks like," Perry said.

Heavy rain meant the start of the final round was delayed.