World No.1 Jon Rahm is still shaking his head 10 days after losing a stunning head-to-head duel with Australia's Cameron Smith as he predicts more low scoring this week.

Smith and Rahm went shot for shot in the final group for the last two days of the Tournament of Champions in Hawaii before Smith prevailed by one shot with a PGA Tour record 34-under score.

That was despite US Open champion Rahm equalling the course record at Kapalua with a 12-under 61 in the third round and tying the tour's record for birdies in a 72-hole event with 32.

"I never thought ever in my career I would shoot 33-under and not win," said Rahm on Wednesday.

"It was a bit of a bittersweet feeling."

Rahm warned to expect more of the same in La Quinta, California where The American Express tournament will be held on desert courses ripe for the taking.

This week's tournament will utilise three courses: PGA West (Pete Dye Stadium Course), La Quinta Country Club and PGA West (Nicklaus Tournament Course) and Rahm expects golfers will need to crack the 20-under barrier to have a shot at winning.

"If the wind doesn't pick up, you're going to have to go out there and post a score. But we all know it, so it's almost like a green light to be aggressive," Rahm said.

"One of the reasons why that happens is because after the overseed these greens are in such a good condition that it enables players to make putts and if you combine it with good ball striking you're going to have some low rounds."

Rahm won this PGA Tour stop in 2018 and was scheduled to return in 2021 before sitting out after tweaking a muscle.

He won't have Smith to contend with this week, with Jason Day and Brett Drewitt the only Australians in the field.

He will play the first three rounds with Tony Finau and two amateurs before the leading 65 professionals move on to the final round at the Stadium Course.