16 July 2010 05:35 GMT

It was a tale of two halves over the Old Course on the first day of the 150th Anniversary Open Championship. The morning starters were blessed with flat, calm conditions, while those who played in the afternoon had to contend with rising wind and blasts of heavy rain. No one took greater advantage of the benign course than 21-year-old Irishman Rory McIlroy who set the lowest first round score in the history of the Championship with a nine-under-par 63.

Tiger Woods, seeking his third successive win at St Andrews after victories in 2000 and 2005, is four shots behind in a large grouping on five under that also includes home favourite Lee Westwood, YE Yang, winner of the 2009 USPGA Championship, and former US Open victor Lucas Glover.

But Colin Montgomerie was struggling to hold together a level-par round before he fired his tee shot out of bounds at the 17th. Three off the tee, he put his fourth in the Road bunker and recovered from a near impossible lie before holing the putt for a six. But it all added up to a 74. Heavily-backed Masters champion Phil Mickelson also had a torrid time as he returned a 73, the same score as double champion Padraig Harrington and last year’s almost-champion Tom Watson.

McIlroy has a history of low scoring, starting as a 16-year-old when he returned a 61 over the championship course at Portrush. In eight previous rounds over the Old Course, six as an amateur, he has never been higher than 69 and at the Quail Hollow Championship this year in America he won with a final round of 62. “I probably got more of a buzz from the 61, just because I was 16 and it was the first time I really went low,” he recalled. His shot of the day was undoubtedly the six-iron he hit high and stopped quickly at the 17th, but he failed to convert the birdie putt.

His lead was reduced to two shots by an impressive round from South African Louis Oosthuizen who reached the turn in 31 shots and slotted two more birdies before falling victim to the 17th hole in common with the majority of players. He was unable to regain that dropped shot at the last where he finished with a somewhat shaky par. A member of the South African team that won the World Junior Championship in 2000, he has yet to make his mark in the majors, having played in five and missed the cut in every one. But he holds second spot on his own, one shot ahead of a five-man group in third place.

One of the best finishes of the day was achieved by heavyweight Swede Peter Hanson who completed the last four holes of his round birdie, par, birdie, birdie for a 66 to share third place on six under. The highlight was his three at the extended 17th, one of just a handful of below-par scores on the hole all day. The six-under target was set early in the day by playing partners John Daly, the champion here in 1995, and Scotland’s Andrew Coltart, a former Ryder Cup player. Later in the day it was also matched by Bradley Dredge with a blemish-free 66. In 2005 he partnered Stephen Dodd to victory for Wales in the 2005 World Cup. Also on 66 is Steven Tiley, who gained his spot at St Andrews after a play-off in Local Final Qualifying at Scotscraig. He justified his place with six birdies and no dropped shots.

The newly crowned Amateur champion, Korea’s Jin Jeong, dropped two shots in a six-birdie round of 68 that will set a hot pace for the other six amateurs in the field. It was a score matched by Ryo Ishikawa, the 18-year-old prodigy who leads the nine-man Japanese contingent at St Andrews. His only blemish was at the demanding 465-yard 13th hole.

With more than 20 nations represented in the field, young Colombian Camilo Villegas put his country’s name among the leaders with a fine 68, no dropped shots and two birdies in each half.

More than half the field of 156 players finished the day under par and more than 500 birdies were recorded. Tiger Woods said that he had never known a major championship where it took a five under par score to get into the top 10 in the first round. In fact 16 players are on that score or better.

As today’s late starters rue their tough luck and prepare for an early tee time tomorrow, the latest weather forecast is not encouraging — heavy rain at times, becoming drier and brighter by late morning, with increasing wind and sunny spells in the afternoon.