(CNN) -- Louis Oosthuizen is four strokes clear of Paul Casey going into the final round of the British Open at St Andrews, after a superb three-under-par 69 left him on a 54-hole total of 201.
The 27-year-old South African, who led the field by five strokes at the halfway stage, was never overtaken throughout Saturday's play, with two birdies in his final three holes, including a 40-fooot monster putt at the 16th hole, helping him keep his rivals at bay.
With conditions slightly calmer on the famous Links course than experienced on Friday, Oosthuizen -- who has missed the cut in seven of his previous eight major tournaments -- now stands on the brink of a famous victory.
Casey, who is bidding to become the first Englishman to win a major since Nick Faldo in the 1996 Masters, carded a five-under-par 67 to lead the chasing pack, while Germany's Martin Kaymer fired a 68 to lie a further three strokes in arrears.
This year's Masters runner-up Lee Westwood, Sweden's Henril Stenson and Spain's Alejandro Canizares are all tied for fourth place on 209 and with two-time U.S. Open winner Retief Goosen the only previous 'major' champion in the top 17, it appears a certainty that a new name will appear on the famous Claret Jug.
World number one Tiger Woods struggled to a second successive one-over par 73 to share 18th place on three-under-par 213.
"I hit the ball good," Woods told reporters. "I just didn't get anything out of the round. I couldn't build any momentum and wasn't making any putts."
Northern Irishman Rory McIlroy, who equalled the lowest round in major history with an opening 63 but experienced the worse of Friday's weather on his way to an eight-over-par 80, carded a 69 to lie on 212 with one round remaining.