South African Louis Oosthuizen fought off Paul Casey to seize a four-stroke lead over the Englishman after Saturday's third round of the British Open at the wind-swept Old Course. Oosthuizen, whose seven missed cuts in eight prior majors include three at Opens, birdied two of the last three holes to fire a three-under par 69 and stand on 15-under 201 after 54 holes at the legendary links course. “I felt like I swung it really well all day and probably left a few more birdies out there,” Oosthuizen said. “But 69, I'm really happy. Over the moon really.” Not since American Tony Lema in 1964 has a first-time major champion been crowned at golf's birthplace, but such a fate seems assured Sunday as two-time US Open winner Retief Goosen is the only prior major winner in the top 17. “It means everything to everyone, but the Open at St. Andrews would be something special,” Oosthuizen said. “It's one of those things you dream of.” Casey, hoping to be England's first major champion since Nick Faldo won the 1996 Masters, fired a 67 and hopes to do so again to catch Oosthuizen, although he has never managed a top-5 finish in 29 prior majors. “I would love to replicate that,” Casey said. “I'm not sure it would be enough with the way Louis is playing, but I was very happy with that.” Following in Faldo's footsteps for a historic English major victory at St. Andrews would be a dream come true for Casey. “I'm not sure I can describe what it would mean. It's the ultimate for me,” Casey said. “I desperately want to be a major champion and I think I have the ability, and I think I'm working hard enough, but that doesn't guarantee anything.” Germany's Martin Kaymer, seven strokes adrift in third on 208, sees little hope anyone but Casey can deny Oosthuizen the Auld Claret Jug. “Too far away would be probably seven, eight shots,” Kaymer said. “I don't really see myself shooting a 63 and I'm not expecting them to shoot 73 or 74.” England's third-ranked Lee Westwood, this year's Masters runner-up and third in the two majors before that, shared fourth on 209 with Swede Henrik Stenson and Spain's Alejandro Canizares. World No. 1 Tiger Woods, a 14-time major champion seeking his first title since a sex scandal last November destroyed his iconic image, struggled to a 73 and shared 18th, 12 strokes off the pace. There was little hope Woods could pull off an unprecedented third Open win at St. Andrews. Woods failed with a new putter on a day when kind pin placements by the Royal and Ancient Golf Club cracked the door for a run at the lead which only Casey nudged wide open. Dustin Johnson was seventh on 210, one stroke ahead of countrymen Nick Watney, Ricky Barnes and Sean O'Hair as well as Goosen. Northern Ireland's Rory McIlroy, Spain's Sergio Garcia and South Korea's Jin Jeong, who won last month's British Amateur, were among six players on 212.