CHICAGO (AFP) — Two-time major winner Dustin Johnson fired a nine-under par 63 to seize a three-stroke lead after Friday's opening round of the LIV Golf Chicago Invitational.

The 38-year-old American enjoyed a bogey-free 18 holes to start the 54-hole event at Rich Harvest Farms, with the winner set to collect $4 million from a $25 million purse.

"I struck the ball really well," Johnson said. "I hit it really close. I holed a lot of putts inside 10 feet."

Australia's third-ranked Cameron Smith, who won the British Open in July at St. Andrews, was second on 66.

"I was hitting good putts but they weren't going in," Smith said. "At the end they started going in. I hope I can keep it going."

American Matthew Wolff was third on 67 with Sweden's Henrik Stenson, England's Lee Westwood, American Charles Howell and Australian Matt Jones sharing fourth on 68.

"It was a good day," Howell said. "The wind picked up. It gets your attention on some of the holes."