Australia's Marc Leishman leads by one shot after the opening round of the Tournament of Champions, the first PGA Tour event of 2018.

The former PGA rookie of the year opened with one of eight birdies and finished on six under in Hawaii.

An eagle at the par-five fifth helped world number one Dustin Johnson to a four-under 69 - two shots back.

World number two Jordan Spieth is eight shots back after a 75, while defending champion Justin Thomas is on two under.

Spieth dropped two shots on each of the front and back nine but had birdies on the fifth and ninth.

Leishman had the best PGA Tour season of his career last year with two wins and he was pleased with his opening round in the event, which features a 34-player field made up of last season's tournament winners.

"I played well, drove the ball pretty well - with the exception of a couple of drives - and the putter was really, really solid," he said.

"It's not a given I'm going to play well. I've got to keep working, but confidence certainly makes it easier to play well."