LOS ANGELES -- Jordan Spieth stood over an 8-foot par putt on the final green at the Northern Trust Open on Thursday afternoon. It was the kind of putt he's made numerous times over the past few years, the hallmark of a game that has helped him ascend to No. 1 in the world.
This time, he missed -- and then he missed the next one, too.
It was emblematic of an uncharacteristic round for Spieth, who posted an opening-round 8-over 79 for the third-worst score of his PGA Tour career.
"It's just a day to forget," he said afterward. "It's one in, hopefully, every couple years. I've shot 80 before. I've shot in the 80s a couple times on tour.
"In the course of a career, I imagine it's going to happen. Just unfortunate when it actually does."
Spieth's worst score in a PGA Tour event came in the third round of the 2013 Memorial Tournament, when he posted an 82. Thursday's round was his worst score since an 80 in the third round of the 2014 Tour Championship.
On Thursday, the statistics were staggering for a player of his caliber.
He posted eight bogeys before that final-hole double-bogey. He found nine of 14 fairways and half of the greens in regulation, but really struggled around and on the greens. For the day, Spieth scrambled for par just twice in nine opportunities and needed a total of 34 putts.
Even more bizarre was that there was no sign he was on the verge of posting a big number.
Just one month ago, Spieth opened the 2016 campaign by shooting 30 under to win the Hyundai Tournament of Champions. At last week's AT&T Pebble Beach Pro-Am, he parlayed a slow start into a share of 21st place. And entering this week, he called Riviera Country Club one of his five favorite courses on the PGA Tour schedule, as evidenced by his performance last year, when he missed a playoff by a single stroke.
"I tried to do better today, even when it wasn't going my way, to just be quiet, stay focused and try and make the next shot," he said. "None of them seemed to go in, but at least that's what I was doing."
Spieth didn't play Riviera on Wednesday, when the course incurred heavy rain at times, changing the conditions from fast and firm to softer than usual.
"I just had a really tough time trusting the way that the course conditions were, and that certainly wasn't all of it, but that was a good amount of it to start with some in-between numbers and just seemed to be anywhere you really shouldn't go, I went," he admitted. "It's just a day to forget, and I won't think much on it."
Perhaps the most telling number from the day was 16 -- as in, the difference in strokes between Spieth and leader Camilo Villegas, who posted a 63.
Rory McIlroy, making his first PGA Tour start this year and his debut at Riviera, opened with two quick birdies and added two more on the front nine for a 67.
Even despite not having any expectations of a 79, that didn't have Spieth any less confident afterward.
"I'm not throwing this tournament away," he insisted. " believe that I can shoot 10 under par on this golf course. There's a 9-under round right now, and I think I can do that. I'm not packing it in by any means."
Information from The Associated Press was used in this report.