Australian Open: Spieth shares lead after McIlroy blows up

American Jordan Spieth shot a two-under-par 69 for a share of a one-stroke lead with locals Greg Chalmers and Brett Rumford after blustery conditions caused chaos in the third round of the Australian Open on Saturday.

Firm greens and difficult pin positions but most of all the gusting wind left Spieth, Chalmers (71) and Rumford (69) on five-under -- a leading score unchanged from Friday -- with only five other players below par for the tournament.

While Adam Scott was among them in a share of fourth with fellow Australian Rod Pampling after both shot 69s, Rory McIlroy suffered a spectacular mid-round collapse that saw the world number one drop five shots in two holes and finish with a 76.

Spieth described conditions as "brutal" and was pleased with his mix of five birdies and three bogeys, one of which came at the ninth hole when his approach shot hit the pin and bounced back off the green.

World No 3 Scott snared his third birdie of the day when he sent a 25-foot putt snaking across the green at the 17th but would have gone even lower had his putter otherwise been working as well as his irons.

Pampling fired the shot of the day with an iron from 120 meters for an eagle at the 10th and could have had a share of the lead had he not missed a three-foot birdie putt on the 18th.

McIlroy's driving was to blame for his slump as he found thick scrub at the ninth for a triple bogey and went into the trees for a double bogey at the 10th to plummet down the leaderboard.

The Northern Irishman ended the day with a share of 14th on one-over but is still only six shots off the pace as he looks to defend the title he won last year.