Australian Jason Day made a solid start to the World Challenge to be in a tie for eighth place after the opening round.
Day carded five birdies in his one-under-par 71, but two late bogeys soured his round at Thousand Oaks in California.
The 24-year-old has endured a tough season but will be hoping to end on a high with a $4million purse up for grabs for the elite 18-man field.
He trails Nick Watney by four strokes after the American carded a brilliant back nine on his way to a 67.
Watney parred his opening eight holes, but stormed to the lead with four birdies on his final six holes.
Compatriots Keegan Bradley and Jim Furyk, and Northern Irishman Graeme McDowell, are two shots back in a tie for second place.
Like Watney, McDowell also found the back nine easy to pick up shots, with four birdies on the home stretch, while Bradley will be left to rue a final-hole bogey that saw him drop from outright second place.
Former world No.1 Tiger Woods is in the mix after a 70 on Thursday left him in a tie for fifth place with Bo Van Pelt and Webb Simpson.
Woods struggled with his swing all day, but still managed three birdies and just one bogey, while Van Pelt recovered from a disastrous triple bogey on the par-five 11th with five birdies in his final six holes.
"I didn't hit it very well today so it was nice to scrape out a good score," Woods said on Sky Sports.
"It's not bad (out there). It didn't rain today, it was overcast and there were some moments when it got a little warm. It's nice, it's not uncomfortable and hopefully we can dodge that storm on Sunday."
Masters champion Bubba Watson and Hunter Mahan are tied with Day at one-under, while Englishman Ian Poulter is in a group of five at one-over.