2010 Open champion Louis Oosthuizen birdied the 72nd hole from short range to finish the 148th edition of the tournament under par.
Oosthuizen birdied two of the first five holes to get his day running but could not capitalize on some fine play with his birdies at 9 and 10 offset by bogeys at the eighth and rather disappointedly at the par 5 12th hole.
A bogey at the penultimate hole left Oosthuizen on level for the championship but the South African showed his class with a close-out birdie to dip into red numbers.
He is currently in a share of 34th place – a Sunday move up of some 16 places – as it stands.
Oosthuizen carded rounds of 70-72-72-69 this week at Royal Portrush with his work off tee letting him down. He averaged
55.36% fairways hit with his iron play moving to 73.61% – a gain of 10% on the field.
On Sunday, he tied his best numbers in the putts per round category with 1.61 matching his effort on Thursday.