Jason Day has allayed fears of his Masters hopes with a four-under par 68 to open the Zozo Championship in California.

Day withdrew from the CJ Cup early in the final round last week with a neck injury.But he played nicely today with four birdies and no bogeys.

"I mean, it's fine," Day said after his round. "Just obviously not 100 percent, but I've got to just keep pushing through it. It's a quick turnaround, you know what I mean? So I understand kind of what I need to do, so I've got to just keep getting treatment and keep moving on. I think overall I'm glad that I got through today, which was good."

Meanwhile another Queenslander, Cameron Smith, was the best of the Aussies on the opening day with a seven-under 65 that put him inside the top 10 behind Sebastian Munoz of Columbia who shot a 64.

Another of the eye-openers was Tiger Woods' opening round of four-over-par 76.

MEANWHILE Minjee Lee began with a two-under-par 70 at the LPGA Tour's Drive On Championship in Georgia to be tied-15th after the first round.

Zozo Championship leaderboard

Drive On Championship leaderboard