South Africa's Oosthuizen finishes 67 to share US Open lead
Oosthuizen, the 2010 British Open champion who began on the back nine, sank a seven-footer at the par-3 eighth and a six-footer at the par-5 ninth to finish off a four-under par 67 and match American Russell Henley for the 18-hole lead.
"Good so far. Lots of golf left, but a good start. Just want to focus on the second round," Oosthuizen said Friday. "Those two putts, take a lot of confidence out of that coming into this next round."
World number 18 Oosthuizen was among 36 players still on the course when play was halted Thursday, the result of a 90-minute morning fog delay at the formidable oceanside layout.
He two-putted from 36 feet at the eighth and from 60 feet on the ninth.
"I'm glad I didn't have to do that last night with greens being a lot bumpier," Oosthuizen said. "It was probably a bit faster this morning than it would have been last night, but I couldn't see anything last night."
Oosthuizen, who has never won on US soil, has finished second in five majors since his breakthrough victory 11 years ago at St. Andrews, most recently at last month's PGA Championship.
"I still need to get myself in a good spot Sunday and hopefully then I'm going to have a good day," Oosthuizen said. "This golf course, there's a lot of things that can go sideways quickly, so you need to keep focus and play well and be calm.
"With a US Open, I know you've got to be so patient, just knowing that everyone is going to make mistakes and just try and do as well as you can."
World number 63 Henley, who hasn't won a PGA title since the 2017 Houston Open, has never finished in the top 10 in a major.
Sharing third on 68 were Spain's Rafa Cabrera Bello, who chipped in for eagle from 57 feet at the 18th in a bogey-free round, and Italy's Francesco Molinari, the 2018 British Open winner.
Masters champion Hideki Matsuyama of Japan and Spain's third-ranked Jon Rahm, who raced sunset to finish Thursday, were among six players who shared fifth on 69.
Also there were four-time major winner Brooks Koepka, seeking his third US Open victory in five seasons, and fellow Americans Hayden Buckley and Xander Schauffele.
They were joined Friday morning by Japan's Rikuya Hoshino, who has won two titles in the past two months on the Japan Tour.
Hoshino, ranked 78th, dropped his approaches inches from the cup at the eighth and ninth holes to set up birdies that put him into the top 10.
The pack was nearly joined by Sebastian Munoz but a closing double bogey dropped the Colombian to 71.
Rahm's US Open preparations were disrupted after he was sent into Covid-19 quarantine last week following a spectacular third round at the Memorial, forced to withdraw after taking a six-shot lead for 54 holes.
Twilight run for Rory
Trying to finish before dark Thursday produced a wild closing spectacle with four-time major winner Rory McIlroy running up the 18th fairway to complete a 70 in the twilight gloom.
Defending champion Bryson DeChambeau, who struggled to a 73, was at the driving range in the dark working on his trademark long tee shots.
World number one Dustin Johnson, trying to hold off Rahm and number two Justin Thomas to keep the top spot, opened with a 71, two strokes better than Thomas.
Hometown star Phil Mickelson, trying for a seventh career major win to complete a career Grand Slam, stumbled to an opening 75, managing only one birdie.
The left-hander, who turned 51 on Wednesday, has finished second a record six times in US Opens.
Mickelson won last month's PGA crown at Kiawah Island to become the oldest major champion in golf history.