Coetzee made an eagle and seven birdies to move a shot clear of compatriot Dawie van der Walt and Briton Steve Webster, who started his round with a spectacular albatross at the par-five 10th hole.
"It was 254 yards to the pin, slightly into the wind off the left," the Englishman told the European PGA Tour website.
"It was a five wood and I hit a great shot, obviously straight at it," he added after becoming the first player to start a European Tour event with an albatross.
"I have never been three under through one before and you wonder is this my day or have I had all my luck on the first hole, but I played great after that."
Four-times major champion Ernie Els chipped in for an eagle at the last and a round of 67, the same score as American John Daly, and Sweden's world number three Henrik Stenson carded a 68 after missing the cut in Abu Dhabi last week.
U.S. PGA Champion Jason Dufner began with a solid round of 70, three shots better than defending champion Chris Wood of Britain.
- Sports & Recreation
- Dawie van der Walt