By Simon Evans
AUGUSTA, Georgia (Reuters) - Americans Fred Couples and Jason Dufner grabbed the clubhouse lead at the Masters on Friday with several players just a stroke behind on a tight leaderboard.
Spain's Sergio Garcia looked set to join the American duo atop the leaderboard but bogeyed the par-four 18th to finish at four-under 68, a shot off the pace along with Lee Westwood (72), Louis Oosthuizen (72), Rory McIlroy (69) and Bubba Watson (71).
The 52-year-old Couples mixed seven birdies with two bogeys for a five-under-par 67, matching the second round score he shot at Augusta National in 1992 when he won the Masters.
Overnight leader Westwood had parred his first 10 holes and produced two birdies on the back nine but undid a lot of his work on the final hole where he three-putted.
World number two McIlroy started the day four shots off the pace but the Northern Irishman made a solid start with three birdies on his first seven holes, including a 35-foot birdie putt on the par-three fourth.
He briefly had a share of the lead, after a birdie on the 15th, but slipped back after he bogeyed the 17th hole.
South Africa's Oosthuizen, who began the day tied for second, had a rough start to his round with a double-bogey seven on the second hole before a strong finish that included three birdies on his final five holes.
But the surprise face among the leaders was Couples, who plays mainly on the senior Champions Tour but showed has vast understanding of the course where he won his only major.
The former world number one, who started the day in a share of 29th place, had two bogeys and five birdies on the front nine and was flawless the rest of the way, making birdies at the 15th and 16th to move to five-under.
Dufner has recently made a habit of getting into the lead in the first half of tournaments only to fade at weekends but he will be looking to go one better than at last year's PGA Championship where he lost in a playoff to Keegan Bradley.
Four-times Masters champion Tiger Woods produced two birdies and two bogeys in his first eight holes.
Australian Jason Day, joint runner-up last year, withdrew from the event with an ankle injury after seven holes of his second round.
(Editing by Frank Pingue)