SOUTHAMPTON, October 16, 2013 (AFP) - Scott had five birdies without a bogey in a seven-under par 64 at Port Royal Golf Course, erasing a three-stroke overnight deficit in the four-man unofficial event.
He had a winning 36-hole total of eight-under 134.
"I'm thrilled to come out on top," Scott said. "Fun, but a trying couple of days here really, especially today. It felt like a long round out there but I was happy with the score."
Overnight leader Rose of England stretched his lead to four shots through seven holes on Wednesday.
But two bogeys opened the door for Scott and Rose finished with a 69 that left him second at six-under.
PGA Champion Jason Dufner carded a 70 and placed third at three-under.
Defending champion Padraig Harrington closed with a 71 to finish last on three-over 145.
Harrington replaced Phil Mickelson in the field after the British Open champion withdrew.
The event is designed to pit the year's three major champions against each other.
Scott, Rose and Dufner were all first-time major champions in 2013.