Thousand Oaks:Mark O'Meara and Fred Couples -- the two players invited by host Tiger Woods -- posted 6-under 66s on Thursday to lead the $4.1 million Williams World Challenge at Sherwood Country Club by two strokes. O'Meara, who plunged to No. 153 in the world after going without a win for three years, reached all the par fives in two shots and got to 7-under par until a bogey on the 17th dropped him into a tie for the lead. Couples, who had not won since 1998 and is ranked No. 100. He had a 31 on the back nine and closed out his 66 by holing a 9-metre (30-foot) par putt up the ridge on the 18th hole. The "Tiger Picks" were in control on Thursday. O'Meara, with a great approach on the 9th, went on to birdie it. O'Meara with another birdie on the 14th ended the day as joint leader at 6-under par. Fred Couples, Tiger's second choice, also looked in great touch birding the 17th for his 5th birdie on the back nine. Couples ended the day on top of the leader board at 6-under, but only after a monstrous putt on the 18th hole. Scott Verplank shot a 4-under par 68 and was tied with Tiger Woods and Vijay Singh, two strokes off the lead. Davis Love III had a nice approach shot on the 15th hole, he ended the first round at 1-under. Singh played bogey-free, he had a birdie on the 18th hole to finish at 4-under. Colin Montgomerie, though had a bad day finishing off with a 1-over par 73. But he did have his moments like this birdie on the 15th hole. Padraig Harrington with a brilliant bunker shot, ended the day tied with Bernhard Langer at 69, three strokes off of the lead. Host Tiger Woods' putter looked in good touch. The Masters champion got one of his six birdies. Woods ended the first round tied with Vijay Singh and Scott Verplank at 4-under.