Séamus Power complained of a little ring rust but a rollercoaster five-under 68 left him just four shots off the pace in the Sentry Tournament of Champions in windless Hawaii.

The FedEx Cup leader was off in the second group of the day, but while he made eight birdies, he was disappointed to throw in three bogeys at the Plantation Course at Kapalua on a day when Jon Rahm, Collin Morikawa and JJ Spaun opened with nine-under 64s to lead by a shot from 20-year-old Korean sensation Tom Kim.

"It was kind of a sloppy one to start the year off — a lot of mistakes, a lot of poor shots," said world number 29 Power, who is tied for 17th in the 39-man field. "But then I made a couple of putts to hang in there a little bit. 

"As far as rust goes, you're obviously practising and stuff, but it's never quite the same as it's going to be in tournament play.

"But overall, I didn't… well, hopefully, I didn't shoot myself out of it. So, you know, ups and downs, and lots of things to work on."

Power dropped an early shot when he failed with a four-footer for par at the 219-yard second.

But he responded with three birdies in a row - knocking in a 12-footer at the third before following a chip-in at the fourth with a two-putt birdie from 45 feet at the par-five fifth.

He was forced to make par putts of seven and eight feet at the seventh and eighth, but while he birdied the par-five ninth, the short par-four 10th and the 432-yard 12th to get to five-under, he couldn't build on his score coming home.

He took four to get down from just over 100 yards at the 13th to slip back to four-under, and while he made back-to-back birdies at the 14th and 15th, he failed to birdie the 16th, dropped a shot after a poor approach to the 17th and failed to birdie the par-five 18th after hitting his tee shot 367 yards.

"I think it's just a little bit of everything, just kind of mentality, maybe around the greens and stuff like that," Power said. "But you know, it's nothing in particular. It's just kind of getting back into the routine and getting into focus and all that kind of stuff that you're used to doing once you get going on the season." 

Morikawa went out in two-under and started for home with six straight birdies before picking up another shot at the 18th to set the pace.

He was joined in the lead by Spaun (32), who also made nine birdies in a bogey-free 63.

Rahm, who was second to Dustin Johnson on his debut in 2018 and runner-up to Cameron Smith last year, hit just four fairways but still made an eagle, eight birdies and just one bogey to join Morikawa and Spaun at the top in the penultimate match on the course.

As for Masters champion Scottie Scheffler, who must finish solo third at worst to regain the world number one ranking from Rory McIlroy, the Texan is tied for fifth on seven-under after opening with a bogey-free 66.