(CNN) -- Northern Ireland's Rory McIlroy equaled the lowest-ever round at a major championship with a nine-under-par 63 on the opening day of the British Open at St Andrews on Thursday.
The 21-year-old leads by two shots from South African Louis Oosthuizen, and a group of players a further shot back including 1995 winner John Daly and Scotland's Andrew Coltart on a day of low scoring at the so-called home of golf.
World number one Tiger Woods, bidding for his third straight title at St Andrews, is a four shots off the lead after a five-under-par 67. He was joined by England's Lee Westwood and American pair Sean O'Hair and Lucas Glover.
The recent wind and rain gave way to more favorable conditions in the first half of the day and McIlroy put together a sensational round, which featured an eagle two on the par-four ninth and a run of five birdies in six holes from the tenth.
His missed a three foot putt for birdie at the 17th after a stunning approach shot but made amends with a short putt for birdie on the last hole.
"The course was there to be taken apart," McIlroy told BBC Sport after posting the lowest opening round score in the 150 year history of the British Open.
"There are a lot of scores out there which are really good and I'm very happy to be in the clubhouse with a 63."
Woods, winner at the Old Course in 2000 and 2005, is appearing outside the U.S. for only the second time since his career was derailed by revelations of a string of extra-marital affairs.
The 14-time major champion, who finished fourth at the Masters and U.S. Open this year, made a bright start to his opening round, reaching three-under-par after nine holes.
He appeared at ease with his new putter as he made further birdies at the 12th, 13th and 14 before dropping a shot at the 17th and missing a 10-foot putt for birdie on the last.
"It was a good start," Woods told the BBC. "Guys are being really aggressive and tearing up the course.
"You have to shoot five under just to be in the top 10. I've never seen a major championship like it.
Daly, whose colorful career has included battles with alcohol, weight and gambling, was the early pacesetter as he stormed to seven-under-par after 11 holes, but a dropped shot at the 17th saw him fall back into a share of third place.
The weather changed for those who went out in the second part of the day, and world number two Phil Mickelson struggled with the conditions, carding a one-over-par 73.
U.S. Open winner Graeme McDowell, from Northern Ireland, also failed to make a big impact as he recorded a one-under round of 71.
Among the former British Open champions on display, five-time winner Tom Watson and Padraig Harrington carded 73s, while Nick Faldo and Todd Hamilton struck level par rounds of 72.
Justin Rose, who has won two of his last three events on the PGA Tour, is two under par, with his fellow Englishman Ian Poulter a further shot back after a 71.