Rahm wins in Hawaii after Morikawa wipeout

Collin Morikawa has endured a spectacular wipeout, even by Maui standards, as Jon Rahm came from seven shots behind to win the PGA Tour's Tournament of Champions in Hawaii.

Rahm was six shots behind on the 13th hole at Kapalua, on the popular Hawaiian surfing island of Maui, when he ran off three straight birdies and a 12-foot eagle putt. His final birdie gave him a 10-under 63.

"If you told me at the beginning of the round ... I was going to do what I did I don't know if I would have believed you," Rahm told broadcaster NBC.

"But at that point it's not like winning is really that in mind, you've just got to get to work and start making birdies and that's what I did.

"On 15 is when it truly became reality."

Morikawa had gone 67 holes without a bogey on the Plantation Course when it all fell apart.

He looked in a state of shock as he walked down the 17th fairway, leading by as many as seven shots during the final round and suddenly finding himself two shots behind and running out of hope.

He wound up tying a PGA Tour record for losing the largest 54-hole lead at six shots.

Asked how he felt after going so close, Morikawa said: "Sadness. I don't know. It sucks".

"You work so hard and you give yourself these opportunities and just bad timing on bad shots and (it all) added up really quickly", he said.

"(I) don't know what I'm going to learn from this week, but it just didn't seem like it was that far off. It really wasn't."

Seven other players have done that, most recently Dustin Johnson in 2017 at the HSBC Champions in Shanghai.

Rahm finished at 27-under 265 to win by two shots over Morikawa, who birdied the 18th hole - his first birdie since No.6 - to close with a 72.

It was the second such collapse by Morikawa in a little more than a year. He closed out 2021 at the Hero World Challenge and had a five-shot lead with a chance to reach No.1 in the world with a victory. He shot 76 and finished fifth.

Masters champion Scottie Scheffler had a chance to return to No.1 this week if he finished in a two-way tie for third or better. He had to settle for a 70 and tied for seventh.

It was a small measure of redemption for Rahm, who last year finished at 33-under par at Kapalua.

It was a PGA Tour record for that lasted only a few seconds before Cameron Smith finished at 34 under to win by one.

Rahm - who goes home with $US4.2 million ($A6.1m) - is now 60 under in his last two appearances at Kapalua.

Australia's sole representative Adam Scott shot a fourth-round 69 to finish 29th at 13 under.