Derksen was a shot clear of Mardan Mamat of Singapore and late finishing Tony Carolan of Australia, who closed with an eagle on the par-5 18th to move into a share of second at 7-under 65.
Englishmen Lee Westwood and John Bickerton and Irelands Damien McGrane were two strokes back in the event co-sanctioned by the Asian, European and Australian tours.
New European Ryder Cup captain Colin Montgomerie and American Anthony Kang, who won the Malaysian Open last week, were at 5 under in a group of seven that also contained New Zealand amateur Danny Lee, Irelands Peter Lawrie, Spains Ignacio Garrido and Japans Hiroyuki Fujita.
Anthony Kim was a stroke further back after a 68.
After managing just one birdie in his first seven holes, Derksen had four straight from the eighth.
The 35-year-old Dutchman, whose tour European Tour wins including the 2003 Dubai Desert Classic, missed a birdie putt on the 14th, but then birdied three of the last four holes to finish with his lowest round ever on the European Tour.
Its a good start and its always nice to have, but theres a lot of golf to be played, Derksen said.
Mardan, the 2006 Singapore Masters champion, birdied his last three holes to finish a shot off the pace.
Westwood struggled early in his first trip to Australia since 2003 but recovered with birdies on four of his last seven holes.
I started off hitting a couple of poor shots, a couple of pulls and got away with one but I corrected the fault, Westwood said. I started hitting good shots after that and I played well for the last 12 holes.
Westwood was playing in the same group as 54-year-old Greg Norman, playing his first regular, non-senior tournament appearance since last years British Open, where he led after three rounds and finished third.
Norman was 3-over after the first round after struggling with his putter, leaving him in danger of missing the cut.
I actually felt pretty good. I putted terribly but that was about it, he said. A 75 was a bit of a shock to me The putter let me down. If Id putted halfway decent I would have shot probably sub-70.
Defending champion Mark Brown of New Zealand was at 2-under and Colombias Camilo Villegas, a two-time winner on the PGA Tour last year, had an even-par 72.