Bettencourt made the tournament as an alternate. The former Reno-Tahoe Open winner needed only 25 putts, joining Tomasulo in holding off a group of four players – including three-time major winner Padraig Harrington – at 4-under.
Harrington and Billy Horschel shared the lead following the morning tee times, battling chilly and windy conditions.
They were joined at 68 by former Georgia Tech standout Bryce Molder and ex-Georgia star Harris English at 4 under in the afternoon.
McIlroy, who entered the tournament as a final opportunity to prep for next week’s Masters Tournament, opened with 72 and is tied for 45th, five shots off the lead.
The former world No. 1 was 2-under early in his round, which began on No. 10 on the difficult 7,435-yard layout.
However, McIlroy found the water on the par-5 18th when his approach came up short – beginning a stretch of three consecutive bogeys. He was 1 under entering his final hole of the round, No. 9, and missed a 7-foot par putt to fall back to even.
It was hardly what McIlroy envisioned when he added it at the 11th hour.
“More mental than anything else,” McIlroy said. “It’s just about limiting those mistakes. It’s definitely more mental mistakes than physical.”
While McIlroy struggled, Horschel continued to show the form that led to a second-place finish at last week’s Houston Open. Horschel jumped from 60th to 24th on the money list following last week’s performance, and he tied Harrington on Thursday with a final-hole birdie on No. 9.
Horschel had six birdies, including a stretch of four in five holes midway through the round, and he did so despite hitting only 7 of 14 fairways. He and Harrington had just 25 putts each, while McIlroy needed 31.
Horschel has made the cut in each of his nine starts this year on the PGA Tour, a streak he hopes to extend on Friday.
“All in all, it’s a good day,” Horschel said. “I could hit the ball a little bit better, but I did a good job of managing it and making a couple putts.”
Jason Gore and Brian Davis finished a shot off the early leaders, posting 69s before stronger winds and warmer temperatures were expected to take hold in the afternoon.
Former Texas standout Jordan Spieth, playing on a special temporary membership, was 4 under with two holes remaining. The 19-year-old, however, landed near a cactus on his tee shot on No. 8 and took a triple-bogey 8 on the par 5.
Spieth finished with a 1-under 71, good for a tie for 18th with the round ongoing.