Graeme McDowell fired a flawless six-under-par 66 to take a one-shot lead after a calm day of low scoring at the 135th British Open on Thursday.

The Northern Irishman reeled off three consecutive birdies from the ninth, where he holed out from a bunker, before overhauling early pacesetters Greg Owen and Anthony Wall of Britain and Spaniard Miguel Angel Jimenez.

Ernie Els, the 2002 winner at Muirfield, was among a group of nine bunched on 68 while Masters champion Phil Mickelson finished a further stroke back, along with 12 others.

Holder Tiger Woods, playing only his third tournament since the death of his father on May 3, recovered from an opening hole bogey and was two under with three holes to play.

"That was pretty cool," a smiling McDowell told reporters after making the most of benign conditions at the north-west England seaside links.

"I was disappointed not to birdie the last but the 18th tee box has been giving me trouble this week.

"I drove the ball really well in general and didn't make any mistakes," added the 26-year-old, who booked his place at Hoylake in last month's European leg of international qualifying at Sunningdale.

Els, determined to shake off a loss of form following a knee injury last season, also wasted a chance to birdie the par-five last after being bunkered off the tee.

However, the three-times major winner rattled up six birdies and two bogeys to make his best Open start since shooting a 66 at St. Andrews in 2000.

"I didn't play the last hole very well but it's always nice to make a par-saving putt," the popular South African said.

American left-hander Mickelson, eager to banish memories of his final-hole meltdown in last month's US Open at Winged Foot, mixed four birdies with an eagle and three bogeys.

Overnight rain took some of the sting out of a Royal Liverpool layout baked rock-hard after weeks of unrelenting sunshine, yielding a glut of birdies and several eagles.

Englishman Owen, who led the 2001 Open at Royal Lytham after 35 holes, was one of the first to take advantage.

He reeled off six birdies and a bogey to set the initial pace with a round that looked better the longer the day went on.

"I was very calm out there and played really well," he said after picking up shots on four of the last six holes.