LOS ANGELES >> Any chance of Tiger Woods breaking par in his first official PGA Tour event in 10 months ended with one swing Thursday and a five-letter word he wasn’t afraid to say.

Shank.

Woods said his back began to spasm over the final few holes in the Genesis Invitational at Riviera. He said that’s what led to his 8-iron from the middle of the 18th fairway that shot off at a 45-degree angle into the eucalyptus trees.

“Oh, definitely I shanked it,” Woods said. “My back was spasming the last couple holes and it was locking up. I came down and it didn’t move and I presented hosel first and shanked it.”

It was no less shocking for the 48-year-old Woods, even at this stage in his career when his back and legs have gone through more surgeries than he has won majors (15). Woods couldn’t recall the last time he hit a cold shank — basically hitting the ball anywhere except on the clubface — except for making some imaginative flop shots around the green.

At least he put it behind him quickly. His shank was behind some eucalyptus trees that frame the right side of the fairway. The shot called for the same club he had just shanked — 8-iron — for a low punch between the trees. And it came out beautifully to 15 feet.

“I had a small window there and tried to hit a punch-hook 8-iron after I just shanked an 8-iron,” he said. “I said, ‘All right, the next shot is supposed to be the harder shot.’ And yes, it was because I’m having to hit a little punch hook through a little gap there.

“And I pulled it off, which is good.”

He still missed the putt and had to settle for a 1-over 72, leaving him eight shots behind Patrick Cantlay and needing to play better on Friday if he wants to stick around for the weekend and wear his new Sun Day Red apparel for golf and not just the trophy ceremony.

Woods, as the tournament host, was adamant about signature events having a 36-hole cut, and the PGA Tour agreed for the player-hosted events to have a cut to top 50 and ties, and anyone within 10 shots of the lead.

He finished the round in a tie for 49th.

Woods managed five birdies on a pristine day at Riviera, with mostly sunshine and a strong breeze late in the afternoon. There also were plenty of mistakes, which he expected after not facing a field this large (70 players) since the Masters.

He was particularly fooled by the surprising speed of the greens on a course that had been soaked the previous two weeks by the heavy rain in Southern California.

“A lot of good and a lot of indifferent. It was one or the other,” Woods said. “I don’t know how many pars I had — wasn’t many (seven). I was either making birdies or bogeys and just never really got anything consistent going today.”

He got three of his birdies on the par 5s, twice getting up-and-down. He rolled in 15-foot birdies on the par 3s on the front nine. But there were sloppy errors and one bad break. His drive on the famed 10th hole reached the green and ran over the green with such pace it settled a foot away from the back lip. He had to play sideways, chipped 8 feet by the hole and made bogey.

Woods had his ankle fused after the Masters and played twice at the end of last year, his Hero World Challenge (he was 18th in a field of 20) and the 36-hole PNC Championship with his son, Charlie.

He was feeling good enough at his Bahamas event that he hoped for one tournament a month. But he also said he should come to expect more competitive rust from not playing much.

“Making adjustments on the fly like that and the feel for a round and how to make those adjustments, I haven’t done that in a while,” he said. “As I said when we were playing Hero, I was getting better each and every day, but then again I haven’t played in a while again. That’s kind of the frustrating part of it.”

He still drew the biggest crowd, with spectators crammed onto the clubhouse balcony to watch his opening tee shot and lining the entire side of the first fairway, a par 5 where Woods made birdie with a pitch and a putt from right of the green.

The end of the round is what got everyone’s attention. A shank is rare, especially for Woods, but it has been a while since he mentioned back spasms. Woods had four back procedures starting in 2016 until deciding to have spinal fusion surgery.

Woods said he has been experiencing spams at home, but not during competition.

“As far as the physical ups and downs, that’s just part of my body, that’s part of what it is,” he said. “That’s all right. I accept it and accept the challenges.”