Brooks Koepka was pleased with his first round at the US Open, while in-form Phil Mickelson was in an optimistic frame of mind despite struggling in San Diego.
On an interrupted opening day due to fog and weather at Torrey Pines, two-time US Open champion Koepka finished two strokes behind co-leaders Russell Henley and Louis Oosthuizen (through 16) as play was suspended because of darkness on Thursday.
American star Koepka – chasing his fifth major title – set the standard with four birdies in his first 11 holes taking him into a solo lead.
However, two bogeys meant he had to scramble to recover as Koepka ended the day alongside Xander Schauffele, Hayden Buckley, Masters champion Hideki Matsuyama, John Rahm (through 17) and Sebastian Munoz (through 14).
Koepka, who has gone on to win or finish second in six of the last 10 majors which he opened with a score in the 60s, said: "You can't win it today but you can definitely lose it. It was nice to get off to a good start, putted well, drove it well on the back nine, my front, but missed a couple fairways there.
"I missed them on the correct side, which is what you've got to do, depending on where the pin location is and get lucky enough where you've got a decent lie and get it there.
"Pretty pleased. Not the best, but I'll definitely take it."
US PGA Championship winner Mickelson is already facing an uphill task following his four-over-par 75.
Mickelson, who became the oldest major winner when he clinched the PGA Championship ahead of Koepka last month, finished with five bogeys, including back-to-back on the front nine.
"It was a great set up and I had some chances to get the round a little bit better," Mickelson said. "Fought hard, made a lot of short putts to kind of keep myself in it and then I ended up bogeying six and seven.
"Two over would have been a pretty good round and I ended up at four, so I'm a little disappointed about that. I feel like I'm close to putting together a good round."
South African veteran Oosthuizen – through 16 holes – moved into a tie at four under after birdieing the 14th.
Winner of the 2010 Open Championship, Oosthuizen is one of three players to finish in the top 10 at each of the last two U.S Opens.
"I just enjoy playing really tough golf courses. I think somehow I focus a little bit better when I play those courses, knowing that the margin for error is really small," said Oosthuizen.
"Especially around this place, you've got to drive it well, you've got to start it in the fairway, and you're going to have trouble if you're missing fairways around this golf course and I've really been driving it good lately."
Four-time major champion Rory McIlroy birdied his final hole to move within three shots of the lead heading into the second round.
"It was really nice. The birdie is awesome," McIlroy – who posted a 70 – said. "I mean, that putt was pretty, I was sort of like, I think it's straight, I'll hit it straight and we'll see. But it was nice to get in, get an extra hour of sleep tonight and it was a bonus to birdie in as well."