Webb Simpson claimed the PGA's RBC Heritage event with a tournament record score of 22-under 262 as Rory McIlroy failed to ignite on the final day in South Carolina.
The American was untouchable down the stretch at Hilton Head, South Carolina on Sunday, claiming five birdies on the back nine to finish with a seven-under 64.
Simpson's stellar closing run proved to be just enough to edge out Mexico's Abraham Ancer, who finished one shot back after a six-under 65.
The win lifted Simpson to number five in the world, following his victory at the Phoenix Open in February.
England's Tyrrell Hatton, who went into round four with a share of the lead, was ultimately forced to settle for third alongside America's Daniel Berger.
After steaming into contention with an eight-under 63 on Saturday, Hatton was left to rue a wayward tee shot on the 13th which led to a bogey.
A birdie on the 16th then proved too little for the 28-year-old to compete with Simpson's blemish-free back-nine performance.
Rory McIlroy failed to ignite on the final day of the RBC Heritage at Hilton Head in South Carolina.
The Holywood native started the day five shots off the lead at the PGA Tour event, however, McIlroy was not able to make up any ground before the leaders teed off.
An encouraging start saw McIlroy birdie the second hole to get to 11 under, however, he handed the shot back with interest two holes later as he double-bogeyed the par three fourth hole.
Another bogey on the seventh hole sent the world number one tumbling down the leaderboard as he dropped to eight under par, however, he would get one back at the turn with a birdie on the ninth hole.
Yet McIlroy could not find any momentum as he headed for home, and while he remained consistent, five straight pars were of little use in terms of challenging for the title.
Storm warnings and lightning in the Hilton Head area called play to a halt as McIlroy went up the 15th and he returned to the clubhouse on nine under par, one shot worse than when he teed off at the start of play.
McIlroy returned following the extended delay and made birdie on 15 to get back into double digits, and made one more birdie on the way in, picking up a shot on the par three 17th.
The four-time major winner ended with a par four on the 18th to post a one-under round of 70 to finish the tournament on eleven under, and in a tie for 41st.
The result marks the second tournament in a row that the Northern Irishman failed to finish in the top 30.
The PGA Tour continues on Thursday with the Travellers Championship from TPC River Highlands in Connecticut.