The 21st-ranked player in the world opened his campaign with rounds of 74 and 70 for 43rd place heading into the weekend.
His stellar round on day three, however, saw Oosthuizen rocket up the leaderboard and leave his name firmly in contention in the final round. As Oosthuizen finished his round on a 4-under total for the championship, he was five shots behind the lead held by American Charley Huffman.
The lead would later be claimed by American Justin Thomas, who shot a sublime 9-under 63 to finish on 11-under overall. By the end of the round,
Claiming the solo lead was
Oosthuizen said on Twitter after his round: “Happy with today apart from the finish. I’ll be six or more back but will try to get a fast start and see what happens.”
After rising to 6-under on the day, his round came to a grinding halt, however, at the 16th where Oosthuizen made a double-bogey six. A par at the par-five 18th meant Oosthuizen would have been left frustrated from a round that had promised much more.
Oosthuizen began his round with two birdies on his first four holes – on both occasions holing putts outside 10 feet, and added a third by draining a 15-footer on the par-five seventh to rocket up the leaderboard.
Still wielding a hot putter, Oosthuizen guided in a putt of 23 feet on the par-four eighth to get to 4-under for his round. The 2010 Open champion rolled in another putt outside 25 feet on the par-four 11th for birdie to move within two shots of the leaders who had not yet teed off.
My game feels ok so let's see what the weekend brings. It was too hot yesterday so the beard had to go! pic.twitter.com/9OLnmDqTby
His first mis-hit came at the par-four 12th with his short-iron approach, leaving over 45 feet for birdie.
Again, Oosthuizen showed excellent touch on the greens by nestling his putt to within a couple feet of the hole and a definite par. Yet another downhill putt of 10 feet proved no obstacle for Oosthuizen at the par-four 15th as he glided that one in to rise to 6-under.
Oosthuizen is no stranger to starting slowly in majors. In the 2015 US Open, he finished one shot behind
After shooting 7-over 77 in the first round, Oosthuizen shot 199 over his final three rounds, tying the US Open record for the lowest 54-hole score.
Countryman Branden Grace fired a third-round 71 to finish on 1-under going into Sunday.
Thomas Aiken shot 75 to end on 1-over after round three.
Having performed admirably in the first two rounds, Ernie Els struggled on day three, signing for a 7-over 79 to fall back to 5-over.African News Agency (ANA)