WHITE SULPHUR SPRINGS, West Virginia (REUTERS) - Tiger Woods capped his lowest PGA Tour round of the season with a trio of birdies to leave him four shots off the early lead at the Greenbrier Classic on Thursday.

Woods, who has struggled for form all season, mixed seven birdies with a bogey and double-bogey for an opening-round four-under 66 on Greenbrier's Old White Course in White Sulphur Springs, West Virginia.

Coming off a missed cut at last month's US Open, Woods hit 10 of 14 fairways and needed only 25 putts to sit four shots back of clubhouse leader Scott Langley.

The former world No. 1, who started on the back nine, got off to a fast start with birdies on three of his first seven holes before giving a stroke back on his eighth hole of the day, the par-five 17th, to make the turn at two under.

He grabbed another stroke at the par-four second hole and looked to be heading home smoothly until running into trouble at the par-four sixth where he left his approach in the bunker and went on to card a double-bogey.

But Woods responded in splendid fashion with birdies on the next three holes.

Defending champion Angel Cabrera was among the late starters and was one-under after his first hole.