Rory McIlroy showed his vast potential on the oldest stage of all today as he equalled the lowest round in a major to lead the field by two, and a lurking Tiger Woods by four, at the British Open.

British Open Day One: As It Happened

The 21-year-old Northern Irishman produced a flurry of first-round birdies and one eagle to fire a nine-under 63, a new record for the Old Course, as a benign St Andrews was stripped of its defences early on.

With the greens still soggy after yesterday's downpours and not a breath of wind, McIlroy seized the lead from South African Louis Oosthuizen, who is bidding to make his first cut in the championship at the fourth time of asking.

Crowd-pleasing American John Daly was sharing third spot on 66 with Sweden's Peter Hanson and British trio Andrew Coltart, Bradley Dredge and Steven Tiley.

As most of the afternoon starters toiled in the strengthening winds and occasional heavy rain, Lee Westwood made light of the worsening conditions by mounting a charge.

The world number three put together a dazzling run of five straight birdies from the fifth and was denied six in a row when a snaking 30-footer lipped out at the 10th. He eventually finished alongside Woods and a host of other players on 67.

Earlier, McIlroy looked on course for a record 62 when he struck a majestic approach shot to within six feet of the cup at the treacherous 17th 'Road' hole but missed his putt.

‘It sort of went through my mind on 17 that 62 would have been the lowest round in a major,’ the world number nine told reporters. ‘That's probably why I missed ... but it was a fantastic score.

‘I didn't get off to a flying start because I was one under through eight and then the eagle on nine turned things around.’

McIlroy, who beat a top-class field to win the Quail Hollow Championship in North Carolina in May thanks to a course record 62 in the last round, drove the green at the par-four ninth before calmly rolling in his 15-foot putt.

That was the trigger for an inspirational run of five birdies in six holes.

The young Ulsterman suffered his only hiccup at the 17th, which he still parred, before replying with a birdie three at the last.

Elsewhere, the world number one drove off early at the first to a lone cry from the galleries of 'Woods time' and started out with a safe par four.

The 14-times major champion, making his first competitive appearance on foreign soil since the revelations of his extra-marital affairs last year, was getting vocal support from the Scottish fans but rarely acknowledged the applause.

Woods slammed his club into the ground in frustration despite finding the green at the sixth hole but his act of petulance seemed to spark him into life.

He birdied the seventh before flashing a wide grin and tapping fists with playing partner Justin Rose after downing a 15-foot birdie putt at the ninth.

The 34-year-old American, who ditched the putter he had used since 1999 for a new Nike model, looked like staging a surge after notching a hat-trick of birdies from the 12th.

Woods though missed a four-footer for par at the 17th and then drove the green at the last but failed to take advantage as he three-putted from the infamous Valley of Sin.

‘The crowd was great, extremely respectful and it was a great environment to play golf in,’ said Woods.

On the low scoring at St Andrews, Woods added: ‘I've never known anything like it in a major championship before’.

Tom Watson, who 12 months ago came within a whisker of a sixth Claret Jug before losing to Stewart Cink in a play-off, warned against complacency, however, on a course where almost anything can happen.

‘She didn't have her clothes on today,’ the 60-year-old said after missing out with a one over 73.

‘What she gave away this morning she will take away the next three days.’

As ever, the tough links layout proved a great leveller.

Sandy Lyle, the 1985 champion, took a seven on the 17th after his tee-shot found the roof of the Old Course Hotel, while world number two Phil Mickelson wore as exasperated an expression as one could imagine after several lipped-out putts in his 73.

One man who has shown before how to master the course here is Daly. Sporting striking lilac and lime green trousers, his play was equally dazzling on the manicured fairways and greens of the Old Course.

His hellraising days behind him, the lighter, wiser version of the man who won the 1995 title here dubbed himself 'Mild thing' after his 66 earned a share of third.

He made his putter sing as he raced to the turn in 31, five under, before suffering a series of lipouts on the back nine.

His chances of a second win?

‘I think this is the first time I've seen the media centre at the British Open since '95, so who knows?’