The Queenslander, going for a second title at his national open after his 2006 triumph, believes he is playing the best golf of his career and showed why with a six-birdie blitz in his first 10 holes.
He stuttered with bogeys on his 11th and 12th holes but picked up another couple of shots on the run home to stand two shots clear of world number four Justin Rose and four others with a share of second place after carding 68s.
"We had the perfect conditions this morning, teeing off at seven o'clock," the 41-year-old Senden, who has won once on the U.S. PGA Tour, told reporters.
"You won't get much of a better day. I thought there were a lot of birdies out there and there would probably be some good scores this morning."
Australia's top player Adam Scott was also among the early starters but struggled with three bogeys and two birdies on his front nine before steadying his round with a single birdie in an otherwise flawless back nine for a 72.
The world number seven, fresh from a victory at the Australian Masters, stuck with his belly putter and said he had paid the price for being too aggressive at the start of his round.
Eight times major winner Tom Watson, now 63, and Chinese sensation Guan Tianlang, 14, were among the later starters and suffered for it as the wind picked up at The Lakes course.
American Watson said he was "embarrassed" with his round after starting with three bogeys and two double bogeys on the front nine and ending up with a six-over-par 78.
Guan, who next year will become the youngest player to take part in the U.S. Masters after winning the Asia-Pacific Amateur Championship last month, failed to record a single birdie in his round of 82.
"He was unlucky today," his father Guan Hanwen told Reuters. "He lipped out on four holes. He played this tournament to get used to these kind of conditions which he is unfamiliar with."
Briton Rose, who picked up five birdies in his first nine holes, was glad to have taken advantage of his early start to grab a share of second with locals Kim Felton, Richard Green, Brendan Jones and New Zealander Gareth Paddison.
"When you see the draw, you know you have one early time when hopefully the wind will lay down," the Englishman said.
"Wind obviously kicked up in the back nine, got a little bit tricky, but all in all, a good start."
Rose, who has never won a national open, said he enjoyed the challenge of playing in such conditions.
"You have to control your shots, and judge your trajectory - it's a lot of fun playing this kind of golf," he added.
Australian Marcus Fraser was the best of the late starters and also had the best shot of the day when he hit a hole-in-one at the par-three 15th.
He finished with a 69 to share seventh with compatriots Stephen Allan and Nick Flanagan, a shot behind Rose's group.
(Editing by Amlan Chakraborty)