Duke cruised through his first round with 10 birdies, including six on his final seven holes. His lead is one shot over Paul Gow, who opened with an 8-under 64 at Jennings Mill Country Club.
The start of the first round was delayed because of fog and eventually suspended due to darkness with 25 players still on the course. The round will resume at 7:45 a.m. (ET).
When play gets back underway, Craig Lile will have two holes remaining with a chance to catch Duke for the first round lead. Lile was through 16 holes at 7-under when play was halted.
John Merrick and Michael Long are one stroke further back after carding matching 6-under 66s. Justin Bolli is also at minus-6 through 15 holes.
For the time being, everyone is looking up at Duke, who found 11-of-14 fairways and 13-of-18 greens in regulation during his round. He needed just 24 putts on the day.
'The whole key today was we had some really good numbers with our yardages,' said Duke.
The very precise round yielded a bit of history for the 37-year-old Duke. His 63 tied the competitive course record set by Jedd McLuen during the first stage of PGA Tour Q-school in 2000.
'I'm obviously pleased,' Duke said. 'Any time you can make 10 birdies, you're doing something right.'
Gow also has reason to be pleased with his round, which was one of just five bogey-free efforts before play was suspended. He hit 11-of-14 fairways and 17- of-18 greens in regulation.
'I haven't played that good for about 25 years,' said the 35-year-old Gow. 'The course played as easy as it possibly could today.'
Four players -- Kim Felton, Jim McGovern, David Gossett and Kevin Johnson -- share seventh place in the clubhouse at 5-under 67. Another, Zoran Zorkic, is at minus-5 through 16 holes.
Tripp Isenhour, who has already won twice on the Nationwide Tour this season, is nine strokes off the pace after an opening-round, even-par 72.