(CNN) -- Adam Scott doubled his lead over Rory McIlroy to four strokes at the Australian Open on Saturday to put him on course for the "Triple Crown" of Australian golf.
The Masters champion carded a four-under par 68 in the third round at The Royal Sydney Golf Club to finish the day 16-under par.
McIIroy, who played his way into contention with a sparkling seven-under par 65 on Friday, couldn't repeat that form on Saturday and had to settle for a 70 which leaves him 12-under for the tournament.
Three Australians -- Matthew Jones, Richard Green and Max McCardle -- are tied for third on eight under, eight shots behind Scott, who won the Australian PGA Championship earlier in November before adding the Australian Masters title last weekend.
"It's an exciting position to be in. Obviously, (I have) a great chance to win my national championship tomorrow and also win three events down here which is unbelievable. If you'd told me that a month ago I wouldn't have believed you," Scott said.
The 33-year-old conceded a lot could happen given the quality of nearest chaser McIlroy, but he remains confident about his chances of becoming only the second player to win the "Triple Crown" in the same season -- compatriot Robert Allenby achieved the feat in 2005.
"I'm sure he's gonna throw plenty at me tomorrow and it's going to be an exciting day," Scott said. "I'm gonna have to do a couple of things better than I did today, but as long as the eye stays in with the putter then I should be able to hang on."
Whereas world No.2 Scott has enjoyed a year to remember, McIlroy has experienced the exact opposite, suffering a slump in form since switching to Nike clubs and slipping to sixth in the world rankings. But on this evidence, McIlroy's superb touch finally looks to be returning, despite the odd wobble.
After a birdie at the first, the 24-year-old then suffered a double setback, bogeying the fourth and double bogeying the fifth, before getting back on track with four birdies in the remaining 13 holes.
"It wasn't the best of starts. I let Adam get a few shots ahead," McIlroy said.
"He made a few birdies around the turn so I tried to stay as patient as possible and a good back nine probably should have been a couple of shots better. I feel like I left a couple out there on the back nine. Obviously, I've got a tough job on my hands trying to catch Adam."
Meanwhile in South Africa, Charl Schwartzel remains on course to defend his Alfred Dunhill Championship title after shooting a five-under par 67 in the third round at the Leopard Creek Country Club, Malelane.
The 2011 Masters champion finished Saturday on 13-under par, two shots clear of England's Richard Finch and three clear of Frenchman Victor Riu.