Brooks Koepka beats Jon Rahm in play-off to win LIV Golf Greenbrier title
Five-time major champion Koepka, made par on the first play-off hole while Rahm made bogey.
Koepka, whose most recent LIV win came in May at Singapore, said it was his most prized because of his day-long fight with playing partner Rahm.
"This is probably my favorite one," Koepka said. "It's always good when you have to battle good players.
"Jon is a hell of a player. For whatever reason, he has always gotten the better of me a little bit as of late. It feels nice just to get one."
Rahm outdueled Koepka in the final round to win the 2023 Masters for his second major title but Koepka said that didn't add motivation.
"I wasn't thinking about it," he said. "Just one of those things. Let's go play golf. It's a good win."
Koepka fired a seven-under par 63 in the final round while Rahm shot 65 to leave both on 19-under 191 after 54 holes at the Old White course in White Sulphur Springs, West Virginia.
American Jason Kokrak was third on 18-under with England's 51-year-old Richard Bland and Australian Marc Leishman sharing fourth on 17-under.
In the play-off, Rahm's tee shot at the par-3 18th went to the back edge of a bunker. One leg in and the other out of the sand, the Spaniard blasted 20 feet beyond the hole.
Koepka missed his birdie putt but tapped in for par, then Rahm lipped out on his par putt and Koepka had the victory.
Koepka's earlier LIV titles came at Jeddah in 2022 and 2023, Orlando in 2023 and Singapore.
Koepka collected major wins at the 2017 and 2018 US Opens and the 2018, 2019 and 2023 PGA Championships.
Rahm, who also won the 2021 US Open, jumped from the PGA Tour to LIV Golf last December and won his first LIV event last month, taking LIV Golf UK at Centurion in England.
The Spaniard shared fifth at the Paris Olympics earlier this month.
Despite the defeat, Rahm remained second to Chile's Joaquin Niemann in the season standings, with the campaign title to be decided at next month's regular-season finale at Chicago.
Rahm sank a five-foot par putt at the 10th hole to match Koepka for the lead at 16-under and launch the back-nine battle.
Bland followed three birdies in a row with an eagle at the par-5 12th to swipe the lead at 17-under.
Koepka made a tap-in birdie at 12 to match Bland then curled in a 15-foot birdie putt on 13 to seize the lead at 18-under, Rahm making birdie at 13 as well to stay one adrift.
Rahm rallies late
When Koepka curled in a 15-foot birdie putt at the 14th, he doubled his edge to two strokes.
But Rahm birdied 16 and the par-5 17th to grab a share of the lead with Koepka, whose birdie putt at 17 lipped out, and both parred 18 to force the play-off.
Rahm, who fired a 62 on Saturday, opened Sunday with a birdie to reach 15-under and lead by two.
Koepka birdied two of his first three holes to pull within a stroke and both birdied the fourth. Rahm made a bogey at six and Koepka first took the lead with a birdie at seven.
Koepka's Smash, with Kokrak in the lineup, won the team competition on 53-under, defeating Leishman and the all-Australian Ripper squad by three strokes.