The trio all finished their 54 holes on 15 under.

Lee Westwood bogeyed the last to miss the play-off and finish joint fourth alongside Open champion Cameron Smith, who was making his LIV debut.

Johnson carded a five-under par 65 with his sixth birdie of the day coming at the 13th.

He failed to make another birdie and needed par saves at final two holes to make the play-off.

Johnson, who finished eighth in the inaugural Saudi-backed event in London, fourth in Portland and third at Bedminster, became the first American to lift the individual trophy in the series.

He sent his play-off putt racing up the hill and although the ball hesitated when it hit the lip, it then hit the back edge of the cup and bounced in.

"Yeah, it was going a little fast, but it was a good line," said Johnson, adding he felt the 18th "owed me one" after his second shot in regulation ended up in the underbrush alongside the giant scoreboard behind the green.

As well as the first prize, he also earned £654,000 ($750,000) as his share of the team first prize for his 4 Aces outfit, which finished two strokes better than Lahiri's Crushers.