Open champion Cameron Smith closed with a three-under 69 for a three-shot victory in the LIV Golf Invitational-Chicago.
Smith was only briefly threatened in the third and final round as he claimed his first title since switching to the LIV series. One of the key moments was a 10-foot par putt on the 13th hole, and neither Dustin Johnson nor Peter Uihlein could do enough to catch him.
Smith won $4 million from the $20 million purse for individual play.
"I think I had to prove to myself and other people that I'm still a great player, I'm still out here to win golf tournaments," Smith said. "I didn't have my best stuff, but I stuck tough and made some putts."
Johnson (70) and Uihlein (69) each made birdie on the par-five 18th hole at Rich Harvest Farms and tied for second, each earning $1,812,500.
Johnson's birdie enabled his team to win for the fourth straight time, which was worth an additional $750,000 for Johnson, Talor Gooch, Patrick Reed and Pat Perez. In the five events Johnson has played, he now has made just over $12.5 million.
Uihlein's team, captained by Brooks Koepka, finished second, which was worth $375,000 for each team member. With the runner-up finish as an individual and team, Uihlein picked up nearly $2.2 million on Sunday.
Smith's short game did most of the damage. He made enough birdies on the front nine to stay in front, and hit a flop shop to a foot on the par-five 11th for another birdie.
Uihlein made birdie on the 13th and looked as though he might be able to trim the deficit to one shot until Smith made his clutch par.
Smith left no doubt at the end, hitting his approach over the water to four feet on the 17th to take a three-shot lead to the par-five finish, and then holing an 18-foot birdie putt that gave his team a tie for third with Phil Mickelson's team.
Mickelson had his best round since joining Saudi-funded LIV Golf with a 66 and tied for eighth, his first top-10 finish in five events.
Johnson is the only player from the 48-man field to have finished in the top 10 at every LIV Golf event. He was coming off a play-off victory two weeks ago outside Boston.
Smith was No 2 in the world when the 29-year-old Australian signed up with LIV Golf after the PGA Tour season ended, the highest-ranked player to join.
Johnson remains one of the most significant players to sign up, a two-time major champion who was No 1 in the world longer than any player since Tiger Woods.
"He's probably the one who you look at it feeling he's going to be at the top of the leaderboard every week," Smith said. "I hope he thinks the same of me, and hopefully, we can keep it going.
Sergio Garcia, criticised last week for withdrawing from the BMW PGA Championship after one round and showing up on the sideline of the Alabama-Texas football game, had a 67 and tied for fourth with Joaquin Niemann (68).
The next LIV Golf event is in three weeks in Bangkok. The series does not return to America until the final team event at Trump Doral near Miami the last weekend in October.
Smith: Ranking points resolution needed 'quite soon'
Speaking after his victory in Chicago, Smith said a decision on whether he and other competitors in the series will receive world rankings points needs to be made soon.
LIV Golf applied for recognition in the Official Golf World Rankings, which play a key role in deciding entry into golf's four majors, in July and their file remains under review.
Smith was one of 12 major champions in the 48-player LIV Golf field this week at Rich Harvest Farms where he secured a three-shot win.
"I suppose there's a lot on the line with the ranking points, getting into majors, stuff like that," Smith, who earned exemption into golf's four majors for at least the next five years with his win at the Open in July.
"There needs to be [a resolution] quite soon, I think. The field here is strong enough and deep enough to where it warrants that, and hopefully it's soon."
LIV Golf has lured players away from the PGA Tour with staggering sums of money, but the financial windfall could come at a cost for those still looking to compete in the Open, the Masters, PGA Championship and the US Open.
Organisers of the majors have not changed their qualifying rules but Smith, who is ranked third in the world, could one day find himself on the outside looking in as, for now, he can no longer earn world ranking points.