Rory McIlroy Implodes as Greg Chalmers Shares Three-Way Lead at Australian Open

World number one Rory McIlroy imploded at the Australian Open on Saturday and lies six shots off leaders Jordan Spieth, Brett Rumford and Greg Chalmers going into the final round.

US Masters runner-up Spieth (67-72-69) joined Rumford (70-69-69) and overnight leader Chalmers (71-66-71) in front at five-under par as The Australian course bared its teeth in windy conditions.

Only eight players were under par after 54 holes in the tournament on a challenging day around the Jack Nicklaus-designed layout.

World number three Adam Scott was well placed to go after his second national open title, lurking one shot behind the leaders with Rod Pampling after a two-under 69 to be on four-under for the championship.

But McIlroy dropped six shots off the pace after a horror round of five-over 76 and has it all to do to defend his Australian Open crown in Sunday's final round.

"The course is on a razor's edge as they are trying to create a golf course that's as unplayable as they can get it without it being so and it's right on that point," Rumford said.

"It's tough, I'm certainly not saying it's easy, you seem as though you are pedalling a million miles an hour going no where."

McIlroy's round faltered with a triple-bogey seven at the ninth after finding the rough off the tee.

The Northern Irishman inexplicably chose not to take a drop, only to further plug the ball into the heavy undergrowth before opting for a penalty out of the tall grass.

He finally got on the green in five but missed a putt to slump to a triple-bogey and tumble down the leaderboard to one-under.

McIlroy lost more ground with a double-bogey six at the 10th to drop five shots in two holes and slump to one-over for the tournament.

He had further bogeys at the 13th and 16th holes only to finish with a birdie at the last to end his demoralising day.

In 54 holes, McIlroy has had 13 birdies, 11 bogeys, one double bogey and one triple bogey.

Scott wrestled with his putter throughout the third round, unable to capitalise on his steady iron play with several makeable putts going astray but unlike McIlroy he stayed in the fight for the lead.

"It was a tough day out there but I think I struck the ball very well, solid, it just felt like it was slow going," Scott said.

"In these conditions, it's going to take an incredible round just to make sure you're in with a chance the last few holes."

Spieth drew level with Rumford and Chalmers with a birdie at the final hole.

"The wind was flipping, it was tough to get the right yardage let alone the accuracy," Spieth said.

"It was a struggle, I felt like I really hung in there nicely. It was very difficult, to grab five birdies on a day like today, if I can do that tomorrow I think I will be in good shape."

Pampling played the shot of the day, an eagle at the 10th hole when his iron approach trickled into the pin from 120 metres out on the fairway.

That took him to five-under and a share of the lead but he dropped back with a bogey at the 17th.