American Russell Henley carded a brilliant seven-under-par 63 to take the halfway lead at the Sony Open in Hawaii on Friday, while Australian Scott Gardiner is six shots off the pace.
Trailing overnight leader Scott Langley by one stroke heading into the second round at the Waialae Country Club in Honolulu, Henley stormed out of the blocks with a birdie at his first hole of the day, the 10th, before repeating the dose at 16 and 18 to turn for home in 32.
A further four birdies on his back nine moved the 23-year-old to 14 under the card, two strokes clear of compatriot Langley - who managed a four-under 66 - and another American, Scott Piercy, who shot a 64.
American Matt Kuchar is a further shot back on 11 under, trailed by compatriots Chris Kirk and Charles Howell III, as well as South Africa's Tim Clark, on 10 under.
American Pat Perez is on nine under, one stroke ahead of countryman Tim Herron, Canada's Stephen Ames, New Zealand's Danny Lee and Gardiner.
The New South Welshman carded a 64 on Friday to follow his 68 in the opening round, leaving him on eight under, two shots ahead of fellow Aussies Alistair Presnell and Matt Jones, with John Senden and Marc Leishman a shot further back on five under.
Dustin Johnson, winner at last week's tournament of champions, was forced to abandon his bid to become the first man to win the first two events on the PGA Tour calendar since Ernie Els in 2003 when he was forced to pull out after nine holes with the flu.