PACIFIC PALISADES, Calif. -- A reporter didn't want to mention the most feared five-letter word in golf when asking Tiger Woods about his next-to-last swing in Thursday's opening round of the Genesis Invitational.

The 15-time major champion said it for him.

"Oh, definitely, I shanked it," Woods said.

Woods, making his 2024 season debut and his first start in an official PGA Tour event since the Masters in April, said he was suffering back spasms during the last few holes at Riviera Country Club.

When Woods attempted to hit an 8-iron from the right side of the 18th fairway, his back locked up. His ball rocketed dead right into a eucalyptus tree and came to a rest behind four trees.

"Well, my back was spasming the last couple holes and it was locking up," Woods said. "I came down and it didn't move, and I presented [the] hosel first and shanked it."

Somehow, Woods was able to hit his third shot onto the green. He two-putted for bogey. It was a disappointing finish to his round, leaving him at 1-over 72. He was tied for 56th when his round ended.

Woods has work to do on Friday if he's going to play on the weekend. In the PGA Tour's third signature event of the season, the top 50 scores and ties will make the 36-hole cut, as will any player within 10 strokes of the leader.

Woods carded five birdies and six bogeys. He posted a 1-under 34 on the front, but then had bogeys on two of the first three holes on the back. He picked up another bogey on the par-4 15th before the mishit on the final hole. He described his opening round as "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. I was either making birdies or bogeys and just never really got anything consistent going today."

Thursday's round was Woods' first competitive one since he finished 18th in a 20-man field in the Hero World Challenge, an unofficial event in the Bahamas in December.

Not surprisingly, most of his game looked rusty. He hit eight out of 14 fairways and 10 of 18 greens. He averaged 290.7 yards off the tee. He needed 30 putts and lost nearly two strokes to the field overall.

"I struggled with the speed of the greens," Woods said. "I couldn't believe how fast they were today even though I made a couple. I ran a bunch by the hole today, it was very stressful. But the golf course is in such perfect shape. Considering the amount of rain they've gotten, to get the golf course this fast is pretty impressive."

Woods, 48, had fusion surgery on April 19 to address post-traumatic arthritis he suffered in a car wreck not far from Riviera Country Club in February 2021. The procedure sidelined him for nearly eight months. Woods said he has been suffering back spasms at home, but this was the first in a competitive round in a while. After Thursday's round, Woods said his right foot felt fine, but his leg was sore.

"Things are a little bit sore, but that's to be expected," Woods said. "That's nothing that we weren't prepared for, and we've got some work to do tonight and tomorrow."

Because Woods is playing such little competitive golf, he isn't used to adjusting his swing and putting stroke during rounds. He competed in only five official events the previous two seasons combined, playing 72 holes in only two of them. He made the cut on the number and tied for 45th at the Genesis Invitational last year.

"I'm going to be rusty, and I have to do a better job at home prepping," Woods said. "We need to do a better job with lifting and treating and continuation of rehab protocols, all those things. I just haven't done it in a while."

Woods will tee off at 2:54 p.m. ET Friday at Riviera.