Rory McIlroy was three off the early clubhouse pace after firing an opening four-under-par 68 at the Pebble Beach Pro-Am in California.
Playing at Spyglass Hill, McIlroy, 28, carded six birdies and two bogeys as his round left him four adrift of Kevin Streelman, Beau Hossler and Aaron Wise.
At Pebble Beach, Graeme McDowell had to settle for a one-under-par 71 after double bogeying the short 17th.
McDowell didn't drop a shot in his first 16 holes before his late mishap.
Playing at the course where he won the US Open in 2010, McDowell found a greenside bunker on the back of the 17th and after getting over-cute with his attempted escape, then took three more form the edge of the green.
The 38-year-old has dropped to 211 in the world rankings after a couple of lean seasons.
The pro-am event sees the professionals and their partners also playing a round at Monterey Peninsula before the final day's action takes place at the famous Pebble Beach public links.
McIlroy's pro-am partner this week is his father Gerry.
|Notifications: Sign up to get golf news sent to your phone|
|My Sport: Sign up to follow golf news|