Davis - who also came from six shots behind to win last year's Australian Open - entered the final round in seventh position and fired a closing 7 under par 65 at Nashville Golf & Athletic Club to finish at 18 under and hold on for a one-shot victory.
The 23-year-old Sydneysider finished ahead of Josh Teater, playing partner Kevin Dougherty who pushed Davis all the way with a closing 66 and overnight leader and defending champion Lanto Griffin who watched his three-lead disappear with a Sunday 72.
For Davis, the victory lifts him to 14th on the Web.com Tour money list and poised to collect one of the 25 cards and full status for the 2019 PGA Tour season.
"I've gone from having no status to having enough status to be able to play events and now to go from that to winning one has been a pretty steep rise over the last month or so," Davis said.
"It opens up the rest of the year, and I'm just looking forward to the opportunities I've got from now on because obviously I've moved up the money list a little bit now, I've got a few more opportunities in my way.''
With pars at the first six holes, Davis gave no indication of a Sunday charge before consecutive birdies at the seventh and eighth holes helped him make the turn at 2 under for the day and 13 under for the tournament.
He went on to play the last 8 holes in 5 under starting with birdies at the 11th, 13th and 15th.
And when Davis rolled in his birdie putt at the par-3 17th, he joined a share of the lead and another birdie at the par-5 closing hole left him with a nervous with four groups still on the golf course.
While Davis headed for the driving range to stay loose, Griffin came to the last hole needing a birdie to force a playoff but could only manage a par.
"First, third and fourth rounds have all been good putting days and today I kept on holing putts when the pressure was a little bit on which is a bit improvement for me. It was just nice I can get it done under pressure," Davis said.
"There were nerves out there, I didn't know the exact situation, but I knew I was up there.
"Went down the last few holes thinking we need to make as many birdies as we can and see how it gets us and obviously it was just enough."
"The Aussie Open was fantastic because it was my first event and it was such a big event but obviously getting it done on this tour, pushing me more towards where I want to get to, the PGA Tour, is really important."
With season's earnings of US$129,831 Davis is just one or two good weeks away from locking up a PGA Tour card before the Web.com Tour's regular season concludes in August.
Davis will compete at this week's Memorial Tournament on the PGA Tour courtesy of a sponsor's invite and also has the Open Championship in July to look forward to.
SIGNATURE HOLES: 8TH AT BENALLA (VIC)
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