South African Louis Oosthuizen today set a testing clubhouse target and knock Rory McIlroy off the top of the leaderboard in the second round of the Open Championship.
Oosthuizen, two shots behind leader Rory McIlroy overnight, added a 67 to his opening 65 for a 12-under-par halfway total of 132 and a three-shot lead over McIlroy, who was among the afternoon starters.
In the second group out today at 6:41am, Oosthuizen survived the wildly fluctuating weather to fire seven birdies and two bogeys, including three in a row from the fifth.
"When we got to the fifth the rain was coming down pretty hard and the back nine didn't look too bright at that stage, but we got lucky at 13 when the wind stopped and turned so we played the last five holes downwind," the 27-year-old said.
"I knew I needed to keep calm throughout the round because I knew it was going to be a tough day and I'm very, very happy."
Oosthuizen, who was a collective 23 over par for his three previous Open appearances before this week, holed from three, four and 10ft for his hat-trick of birdies from the fifth, before driving the green on the 386-yard 10th to set up another birdie.
Further birdies on the 12th and 14th were sandwiched between two bogeys, but the former world junior champion also birdied the last with two putts from long range to complete an excellent round.
After ensuring a late tee time for Saturday afternoon - and only a second made cut in his ninth major - before noon on Friday, Oosthuizen added: "I've never been done so early to be honest. There's more than a day (between rounds).
"I'll watch a bit of golf and try to relax."
American Ricky Barnes had looked like being Oosthuizen's closest challenger when he went out in 32 and birdied the 10th as well to reach nine under, but he then ran up a double bogey seven on the 14th after tangling with one of the Old Course's fearsome fairway bunkers.
England's Paul Casey, reportedly suffering from a bad chest infection, had nevertheless started with three straight birdies and picked up two more to reach the turn in 31.
Four straight pars from the 10th left the Ryder Cup star alone in third on eight under par.
McIlroy, at 21 looking to become the youngest winner of the Open since Willie Auchterlonie in 1893, was not due to start his second round until 1:31pm, but world number three Lee Westwood was one under for the day and six under overall.
Westwood, who has been struggling with a torn calf muscle, picked up a birdie on the fifth and had carded 11 pars despite the occasional heavy showers and fickle breeze.