Branden Grace posted a seven-under 65 in the final round on Saturday, leapfrogging Dustin Johnson and Carlos Ortiz to win LIV Golf Portland.

Two shots behind the co-leaders at the start of the third round, Grace reeled off four birdies in the final six holes, including three consecutive birdies between 15 and 17, to take out the tournament.

With the victory, the South African follows up compatriot Charl Schwartel's win in London at LIV Golf's inaugural event in June.

The South African quartet that makes up Stinger GC - Grace, Schwartzel, Louis Oosthuizen and Hennie du Plessis – could only manage second in the team standings, though, with Johnson's 4 Aces GC taking out first.

"What a day. It's been like this the whole day, the crowd came out and I played flawless golf," Grace said afterwards. "I played, really, really well when I needed to do something special. It came up and I managed to pull it off, but what a great day.

"I knew the back nine, I had to kind of dig deep. Carlos was playing great golf, DJ was coming back and I think, one of the big things for me today was the birdie on 13.

"Then I thought, 'Now, I'm in with it.' Obviously, the finish was just amazing."  

Amid the news former Ryder Cup player Paul Casey defected from the PGA Tour to the Saudi-backed breakaway competition, Grace finished the tournament on 13-under, two strokes ahead of Ortiz who posted a three-under 69 on Saturday.

They were followed by 2020 Masters winner Johnson and another recent defector in Patrick Reed, who finished on nine-under after 54 holes.

Six-time major champion Phil Mickelson finished tied for 40th this week with a 54-hole score of 10-over. Through two LIV Golf events, Mickelson is a combined 20-over par.