After a rough start, Justin Thomas rallies to finish on the fringes of contention

Most kids would have caved after the start 21-year-old Justin Thomas endured on Saturday at Riviera Country Club. Thomas, who started the third round only one shot back of leader Retief Goosen, shot five-over 40 on his front nine.

He hit out of bounds on his opening tee shot at the historic par-five first hole, ending up with a bogey on the easiest hole on the course.

The first three rounds at No. 1 have yielded 220 birdies, 22 eagles, 108 pars and only 10 bogeys.

Thomas followed with a triple at the par-three sixth. He rallied, though, to shoot one-under 35 on the back nine, closing with a birdie three at the par-four 18th hole.

Thomas ended up at four-over 75 for the day but kept himself on the fringes of contention at one-under 212 overall.

Two timers

Deuces were wild for Saturday’s final trio grouping of Goosen, Ryan Moore and Graham DeLaet.

All three made birdie twos on the par-three sixth hole, but that wasn’t the end of it.

All three also made birdie twos at the par-three 16th hole.

The only three par they messed up was No. 14. The group played that hole at a collective two-over. DeLaet and Moore made bogey four on the hole, while Goosen had par.

Carlos Ortiz, who earned his way on the PGA Tour this year with three wins on the Web.com Tour last year, finds himself in contention at five-under overall.

Ortiz, who is from Mexico, is trying to become the first player since Adam Scott in 2005 to win the Northern Trust in his first start.

Ortiz shot a three-under 68 on Saturday, his highlight an eagle three on the par-five 11th hole.

Ortiz said Riviera sort of reminds him of his home course, Guadalajara Country Club, in Mexico.

“It’s actually a pretty similar golf course,” Ortiz said. “There’s a lot of holes that look kind of the same, same grass, same greens.”

Stay tuned

Sunday’s final grouping of Retief Goosen, Graham DeLaet and Sang-Moon Bae will tee off at 10:20 a.m.

The 10:09 grouping will feature Carlos Ortiz, Sergio Garcia and J.B. Holmes.

Defending champion Bubba Watson is in the 9:38 grouping with Ryan Moore and Vaughn Taylor.

Vijay Singh, who turns 52 on Sunday, will tee off at 9:48 with Jordan Spieth and Angel Cabrera.

Singh is trying to become the second oldest player to win a PGA event. Sam Snead was 52 years and 10 months when he won the 1965 Greater Greensboro Open.

Snead, in 1979, was also the first PGA player to shoot his age in a tournament. Snead shot 67 in the Quad Cities Open.

“I’m playing well,” Singh said about his chances. “I just need to, you know, keep in touch with the leaders and just go out there and play my game.”

DeLaet is trying to become the second Canadian to win the Northern Trust Open. Mike Weir is a two-time winner but had to withdraw early this week with an elbow injury.

“I don’t really feel it as pressure,” DeLaet said of trying to follow Weir with a win. “More than anything, we’re a proud nation and we just cheer on our athletes. That’s what I feel more than pressure. I just feel the support from 35 million people north of the border.”

chris.dufresne@latimes.com