Oosthuizen, with a simple swing considered among the most pure in golf, again took advantage of the par 5s at Mission Hills, shooting a 9-under 63 Friday in the HSBC Champions to build a five-shot lead and break a World Golf Championships record that previously belonged to Tiger Woods.
Along with opening a five-shot lead over Ernie Els — his South African mentor — Oosthuizen reached 16-under 128. That's the lowest score to par through 36 holes in any World Golf Championships event since they began in 1999.
Woods had a 15-under 125 at Firestone in 2000, and he was at 15-under 127 at The Grove outside London in 2006 at the American Express Championship. Woods went on to win those events by 11 shots and eight shots, respectively.
Els, who skipped the PGA Grand Slam of Golf early last week because of a minor ankle injury, was nearly as perfect as Oosthuizen. He also had a 63 that vaulted him from 19th place into a tie for second with Adam Scott of Australia, who had a 68.
Shane Lowry of Ireland (68) and Jason Dufner (66) were another shot behind. Phil Mickelson, a two-time HSBC Champions winner, made double bogey on his last hole for a 69 that left him seven shots behind going into the weekend.
Oosthuizen made birdie on all five of the par 5s on the Jose Maria Olazabal-designed course on Thursday. In the second round, he picked up four birdies and an eagle, making him 11 under on the par 5s over two rounds. He nearly had a second eagle on Friday, when he nearly holed out a bunker shot on the par-5 ninths.
Then again, Oosthuizen and the par 5s have gone together nicely this year.
His most memorable shot of 2012 was a 4-iron that he holed for his second shot on the par-5 second in the final round of the Masters for an albatross. It wasn't enough, however, as Oosthuizen lost in a playoff to Bubba Watson.
"You get those days where if you hit it well, you leave yourself in a decent spot for a chip-and-putt for a birdie on the par-5s," he said.
"I think I can reach all of them, which, you know, makes it easy."
Oosthuizen, who won by seven shots at St. Andrews in the 2010 British Open, has won twice this year at the Malaysian Open and the Africa Open, though he has come up short in two bigger events — the Masters and the Deutsche Bank Championship outside Boston, where he finished one shot behind Rory McIlroy.
Now, he is halfway toward becoming the 11th player to win a major and a WGC event.
"I've just been playing really, really solid to shoot low numbers," he said. "I'm in a great position to win it, but it's not even crossed my mind at the moment."
If anyone can catch him, it may be Els, who came back from six strokes down at the turn in the final round of the British Open this year to capture his fourth career major, helped by Scott closing with four straight bogeys at Royal Lytham & St. Annes.
Els is just happy to be playing at Mission Hills this week after falling and injuring his ankle during a tennis match two weeks ago. He said the ankle is still swollen and a little painful, but he's able to hit and walk on it.
"I feel it, but it's all right. You know, what do they say, be aware of the injured golfer," he said with a smile.
Mickelson played a superb front nine with two eagles and two birdies to move into a share of second with Scott at the turn. But his fortunes turned on the 18th when he barely cleared the lake and landed in the rough on a steep slope next to the green. Balanced awkwardly with one foot on a rock and the other on the hill, he got nothing but dirt with his first swing. He popped the ball onto the green with his second attempt but then missed a 10-foot putt for bogey.
"It's disappointing finishing with a double but I played pretty well for the most part throughout the first 12, 13 holes," he said. "I just played a little sloppy coming in."
Scott, the co-leader with Oosthuizen after the first round, made four birdies to keep pace with the South African on the front nine before blundering an opportunity for birdie on the par-5 ninth, which he had eagled the day before. After positioning himself well with a deep second drive that nearly reached the green, the Australian left his chip shot short, setting up a difficult 10-foot putt. He pulled the putt wide by inches and had to settle for par.
Scott's struggles continued on the back nine with three bogeys to go along with his three birdies. Still, he believes he can make up ground on Oosthuizen over the weekend.
"Five shots is just a couple of holes to get back," he said. "There are eagle chances and there's also a lot of trouble so it can all turn around quickly."
Peter Hanson and Watson fell off the pace after trailing by one coming into the day. Hanson slipped to 12th place after carding a 71 and Watson plummeted to 17th after a triple bogey on the tricky par-5 15th. He shot a 72. Hanson needs a win this week to move past McIlroy atop the European Tour money list.