The world number 322, who has never won a European PGA Tour event, birdied the last three holes to finish on 13 under par.
"Every shot is a new shot, and that mantra will be very important for me tomorrow," Dantorp told reporters.
"It's been a decent year so far but I haven't really pulled anything off, so it's nice to head out as leader."
Dantorp, 29, will start the final round one stroke ahead of his compatriot Alexander Bjork, American Rickie Fowler, England's Matthew Fitzpatrick, Australian Scott Hend, New Zealander Ryan Fox and German Marcel Siem.
Fox, son of former All Blacks flyhalf Grant, and Hend shot matching seven-under-par 63s while world number three Justin Rose of England warmed up for next week's British Open at Carnoustie with a solid 67 to join a group of players on 10 under par.
(Writing by Ed Osmond; Editing by Hugh Lawson)
