The joint 54-hole leader with World No.1 John Rahm after posting a spectacular course-record 60 on Saturday, Smith gifted victory to Finau when he drove out of bounds on the first extra hole.

“Just a terrible swing, mate. Just a mis-hit, and in these conditions, you can't mis-hit the ball,” Smith said in the aftermath. “Got a little bottomy and a little bit healy and just blew up in the wind and went a long ways right.

“You know, my driver has cost me a few tournaments this year. That makes mean more determined to try and figure it out before the end of the year.”

Smith watches his drive sail right during the play-off at Liberty National. PHOTO: Sarah Stier/Getty Images.

Both players had finished at 20-under, after Smith closed with a four-under 67 and Finau recorded a final-round-low 65.

Without a win since the 2016 Puerto Rico Open, Finau has been knocking on the door relentlessly for another breakthrough.

RELATED: Inside Finau's winning bag

The 31-year-old has posted 11 top-3s since and 39 top-10s, including five in his past eight majors.

Finau had also lost three tournaments in playoffs.

“This is extremely special. I thought my first one was going to be my most important one but I actually think this one,” Finau said. “It validates the first one but because of how long I've had to wait, I'm a totally different golf player because of how long I've had to wait.

“Nothing has come easy for me. I've lost in playoffs, taken second, third in, major championships. I've persevered and that's the biggest key is I haven't given up on myself and on my team.”

RIGHT: Finau holds the trophy after breaking his win drought. PHOTO: Stacy Revere/Getty Images.

As well as the spoils, Finau rocketed into the lead of the overall FedExCup standings and into pole position for a mega $US15 million ($A21m) bonus pay day at season's end.

Smith has soared from 16th to third in the standings before the second play-offs event, the BMW Championship in Maryland starting on Thursday.

“That's why we're here, we're here for the FedExCup. Luckily for us there's always next week, and we've got two events left to try to make another move, so looking forward to it,” Smith said.

Fellow Australians Marc Leishman, Cam Davis and Matt Jones also progressed after maintaining their positions in the top-70.

But the season is over for former World No.1s Jason Day and Adam Scott after they missed the cut in New Jersey.

- Additional reporting, Jimmy Emanuel