Make that Lodewicus Theodorus Oosthuizen.
"It's my grandfather's name," the 27-year-old South African said. "They call me Louis now."
Well, not everybody. The woman who introduced Oosthuizen for his news conference called him Peter Oosthuizen. Peter Oosterhuis is the former English golf star and occasional television commentator who is 62 now. Still, he remains more famous than Louis Oosthuizen, who, until Friday, wasn't even as famous as the guy announcing the players on the first tee.
But then came a round of golf not often seen in daylong conditions more conducive to sitting by a fire and reading a book than playing golf. That put him on the golf world's radar.
His father is a farmer, he once was a top junior tennis player and the only way he was able to financially navigate his way through the early years of pro golf was with help from Ernie Els' foundation, which backs young golfers from Els' country.
He has played in eight majors and missed the cut in all but one, the 2008 PGA Championship. He was asked, given this record, if he had rented a house in St. Andrews for two days or four. That question would have offended many golfers. Oosthuizen laughed.
"Booked a house through Sunday night," he said. "I was planning on making the cut."
One suspects he wasn't planning on shooting 67-65 and leading after 36 holes. Had you put a nice bundle down on that in Las Vegas, you'd be flying your own Learjet over right now to watch the weekend.
Oosthuizen's lead was as miraculous as the weather was mystifying. He played in the morning, when it rained cats and dogs and rabbits and squirrels. It also blew so hard for most of his round that he described one of his tactics as having to "focus on where you are pointing your umbrella; otherwise, you don't have one."
Oosthuizen — pronounced West-Hi-Zen — said he was proud of himself because "I struggle in rainy situations, and today I got my head around it."
Not so some of the bigger-name leaders who went out in the afternoon, when the rain stopped but the wind got even worse.
First-round leader Rory McIlroy, who had broken 70 in all nine of his previous rounds at St. Andrews, including Thursday's 63, carded 80.
John Daly, wearing red pajamas this time, was ten shots worse than Thursday at 76.
Tiger Woods persevered much better, battling to a 73 that left him within eight.
On Oosthuizen's resume is a 57, shot with friends in 2002, shortly before he turned pro. He used to have a Shrek head cover on his clubs, but his caddie told him it was bad luck.
Why Shrek? It's his nickname.
"It's the gap in my teeth," Oosthuizen said. "My friends say I look like Shrek. And you can't choose your friends, so what can I say?"
Yes, you can. And if Oosthuizen somehow wins out in this war of weather and willpower, he'll have millions of them.