With two-time defending champion Jimmy Walker lagging behind, many of the other Sony Open in Hawaii past champs are thinking repeat.

Of the nine winners at Waialae Country Club to tee it up in the first full-field PGA Tour event of 2016 on Thursday, only Mark Wilson failed to break par, with Walker needing a birdie on 18 to get into red figures.

Vijay Singh, the 2005 champion, is one of five co-leaders at 7 under. Singh was one of four past champions teeing off in the morning who all helped set the tone for a low-scoring first day.

“Less wind this year. So that’s a big deal if the wind doesn’t blow,” said Singh, who carded seven birdies and no bogeys. “I didn’t know what to expect. It was early, so I didn’t know how it was going to turn out.”

None of the four past champs off before noon shot worse than the 3-under 67 of 2012 winner Johnson Wagner, who was rocking the 1970s mustache once again.

It was Wagner’s best round here since he closed with a 67 in tough conditions to beat a group of four by a single stroke for his third PGA Tour win four years ago.

Wagner has missed the cut in his three appearances since, but got it going sinking birdie putts of 23 feet on No. 5 and 16 feet on No. 6.

“‘I’ve had two good weeks here in nine tries, so I’m happy to be sub-70,” Wagner said. “Made some good putts but struggled with my ball-striking when I was coming in trying to make a few more birdies.”

Although it didn’t quite play out the same way Thursday, with the wind staying calm in the afternoon, the morning round is typically where players have the easier time going low.

Ryan Palmer, the 2010 champion, went out in 31 with four birdies on his first nine holes.

A great round was nullified by back-to-back bogeys on Nos. 12 and 13 when he drove it into the rough twice. He flew the green on 12 with his approach and missed a 12-foot putt and then came up short on a 10-footer for par on 13 when he again missed the green in regulation.

It took a wedge on 16 to within 7 feet for birdie on 16 and an up-and-down from 50 yards out on the fairway for birdie on 18 to salvage a 66.

“I love seeing putts go in and it was huge for me to get comfortable,” Palmer said. “You shoot 66 and it sets you up to come out strong tomorrow and get ready for the weekend.”

Like Wagner, Palmer struggled at Waialae in his three appearances following the win, finishing outside of the top 50.

He’s contended each of the past two years, shooting a 65 in his Thursday morning round in 2014 and a course-low 63 in his Friday morning round last year.

“Especially in the morning, when there’s hardly any wind, you don’t want to go out and kick yourself in the foot,” Palmer said. “It’s nice to spend Thursday afternoon relaxing after a good round to get yourself ready for Friday.”

The top 20 also included perennial contender Jerry Kelly, the 2002 champion, who has eight top-10 finishes at Waialae, including a third in 2014 and a tie for sixth in ’15.

“I kept the ball in play. If I missed a green, it was pretty much a fringe,” said Kelly, whose career earnings at Waialae top $2.5 million. “First win came here and it’s just a ton of great feelings.”