World number one Jordan Spieth opened up a four-shot lead on day two of the Hyundai Tournament of Champions in Hawaii.

Twenty-two-year-old Spieth ended the first day of play one shot adrift of overnight leader Patrick Reed, but he moved himself to the top of the field 24 hours later thanks to a nine-under-par round at Kapalua.

Over the 18 holes the current Masters and US Open champion recorded seven birdies and an eagle to move to 16-under-par for the tournament.

"It was a similar round to yesterday. It is nice to have no blemishes on the card," bogey-free Spieth told reporters.

"I want to start the year with a bang, but I'm only through 36 holes, there's a long way to go."

Fellow Americans Reed and Kevin Kisner are Spieth's closest challengers on 12-under, as is Argentine Fabian Gomez.