Giebler, a member of Dalhousie, posted a 3-under-par 69 and a two-shot lead on a hot and breezy Tuesday.
Another Cape Girardeau golfer, Brent Holmes, was one of the two other players to shoot under par.
Holmes carded four birdies on the back nine in his round of 71, which tied him with Jace Long, a two-time state champion while at Dixon High School and a Ping Golf All-American at the University of Missouri.
"I played really solid golf," said Holmes, who plays most of his golf locally at Bent Creek. "I think it was one of the better rounds that I played [at Dalhousie]. With the wind today and the greens firm and fast, there really was no room for error."
"That was really the only bad shot I hit on the back nine," Holmes said.
Holmes said his longest birdie putt was about 12 feet.
"I was just hitting them close," Holmes said.
Holmes teed off in the afternoon, and he turned in some strong iron play amid tough conditions.
The three-man groups will remain the same today, but the tee times will flip from morning to afternoon, and vice versa.
"I'm looking forward to playing in the morning, maybe get a little smoother greens and maybe not as much wind," Holmes said.
Long, who was in Giebler's three-man group that teed off at on No. 10 in the morning, had two birdies and a bogey in his round.
"Today was good. Me and Brevin played really well," said Long, who has won six events at Missouri over the past two seasons, including a school-record four in 2011. "I've been here before, so I know you play to make pars and the round of match play. Basically it's a new tournament once match play starts."
Long, who just competed his junior year at Missouri, played in the U.S. Amateur last year and reached the tournament through the qualifier at Dalhousie.
Giebler had five birdies and two bogeys in his round. Three of his birdies came on the four par 5s, which also produced a bogey.
Giebler started on No. 10 and went on a birdie binge after parring his first five holes. Giebler birdied Nos. 15, 17 and 18.
He moved to 4-under par with a birdie on No. 2, a par 5, but bogeyed the next hole. He shot even par over the front side, with another birdie at the par-3 No. 5 offset by a bogey at the par-5 No. 7.
Brad Nurski, a 33-year-old from St. Joseph, Mo., completed the threesome and shot a 77. Nurski lost a playoff in the Missouri Amateur Stroke Play Championship at Dalhousie in 2009.
Nurksi had played practice rounds with Giebler in the days before the tournament.
"He's playing good," Nurski said. "Obviously it's his home golf course. It's going to be hard to beat him this week. If he keeps playing like this, he's going to be tough to beat for anybody."
Nurski said the wind and fast greens added to the difficulty of the 6,942-yard, par- 72 layout.
ABOVE: David Babcock of Cape Girardeau putts on the ninth green.
RIGHT: Ben Cantrell of Cape Girardeau follows his tee shot on the 13th hole.
The field of 144 golfers will be trimmed to 64 after today's second round. Match play begins Thursday and concludes Sunday.
Mason Good of Warrensburg, Mo., Nick Wilson of Columbia, Mo., Justin Timberlake of Ozark, Mo., and Andrew Luo of Evansville, Ind., all were three shots behind Giebler at even-par 72.
Tim Simmons, a graduate of Central, carded all three of his birdies on the back nine in his afternoon round of 74, which tied him for 11th. Simmons played golf at Evansville University for two years after graduating from Central in 2009, but he said he hasn't played much golf recently.
"I'm not going to say I was surprised, but I wasn't expecting to make all the birdies," Simmons said. "My brother [Travis] told me how tough it played in the morning, and I saw all the high scores, and I said, ‘Well, anywhere close to par is going to be good.' And I just kept hitting pretty decent shots all the way around and made a few putts."
Three double bogeys accounted for Phillips' 6-over total. He offset two bogeys with a pair of birdies in his attempt to make his third trip to match play.
"I feel like I'm in good position," Phillips said. "It was pretty difficult out there today. I definitely didn't shoot myself out of the tournament at all."
Phillips was impressed by the round turned in by Giebler.
"That is an amazing round today," Phillips said. "That wind, it was blowing pretty good, and the greens were rolling pretty quick. To be 3 under, that's a great round."
Ronnie Strong of Jackson followed with an 80, while former Central golfer Blake Driskell shot 81.
Notre Dame junior Brady Dixon of Mounds, Ill., Central junior Travis Simmons and recent Central graduate Corey Connell, who got into the field Monday as an alternate, all shot 82.
David Babcock of Cape Girardeau was at 84, and Lee Wilson of Perryville, Mo., a 37-year-old transplant from South Carolina who competed for the Mineral Area College golf team this year, shot 89.
(ABOVE: Travis Simmons of Jackson blasts out of the bunker onto the eighth green.)
* Two-time champion Ben Godwin of Poplar Bluff, Mo., also shot 76.
* The first day featured a hole-in-one by Bob Meeh of St. Louis. Meeh started on No. 10 and aced his second hole of the day in a round of 80. Meeh damaged the hole on the 11th green with his shot and play had to be halted for about 20 minutes while a new hole was cut about three feet away from the original cup.
Meeh used a 7-iron from 158 yards for his fourth career ace.
"It had a nice little draw, from left to right, and coming down it just kind of slammed into the corner of the hole and took maybe a 3-inch gouge out of it," Meeh said. "Luckily it stayed in there. That's the first time I've seen something like that."
* Second-round play begins at 7:30 a.m. today. Giebler's group will start on No. 1 at 1:18 p.m.