Robert Allenby in 2005 is the only player to have won the Australian Masters, Australian PGA and Australian Open in the same season.
Former Australian Open champion Craig Parry is among a group of players including Greg Norman, Peter Lonard and defending champion Peter Senior to have won all three Australian majors, but Parry did it over 15 years.
"It's hard enough to win once, let alone the next week and now he's trying to win the Australian Open and that's the big one," Parry said Wednesday. "Just the history of it, the great names that have won it, the mystique."
Gary Player won the Australian Open seven times, Jack Nicklaus six and Norman five times.
"Scotty's playing fantastic and the fact that he's had all the pressure on him coming back home to Australia and then delivered ... it's one thing to expect and another to do it," Parry added.
Scott's other major threat to what Australian media are calling the "Scotty Slam" is Rory McIlroy, who admitted Wednesday that "it's been a long year, mentally more than physically."
McIlroy, who has eight top-10 finishes in 2013 but hasn't won a tournament this year, has been embroiled in court cases over his management company and a major sponsor.
But McIlory says he arrived in Australia feeling refreshed from a month-long tournament break.
"I took four weeks off and did some great work with my coach," McIlroy said Wednesday. "Once you start to see results your confidence comes back."
The Australian Open also begins qualifying for next year's British Open at Royal Liverpool at Hoylake.
In the first event in the new Open Qualifying Series for next July, the three players who finish in the top 10 and ties, who have not already qualified, will get a spot at Royal Liverpool.
Only four players in the 156-man field at Royal Sydney have qualified for The Open McIlroy, Scott, Day and Streelman.