Honolulu, HI (SportsNetwork.com) - Paul Casey and Webb Simpson opened up with matching 8-under 62s in Thursday's first round and they share a 1-shot lead at the Sony Open in Hawaii.

Casey is a 13-time winner on the European Tour, but his lone victory on the PGA Tour came at the 2009 Houston Open. Simpson, the 2012 U.S. Open champion, is a 4-time winner on tour, with the last one coming at last season's Shriners Hospitals for Children Open.

Robert Streb, a winner at the McGladrey Classic in October, continues to play well this season as he is tied for third with Camilo Villegas after the duo began the week with 7-under 63s at Waialae Country Club.

Rory Sabbatini carded a 6-under 64 on Thursday and he is alone in fifth. Jason Day, Matt Kuchar, John Peterson, Tim Clark, J.J. Henry and Jonathan Randolph are all tied for sixth at 5-under 65.

Defending champion Jimmy Walker had a solid first round and his 4-under 66 has him tied for 12th with 10 others.

Playing the back nine first, Casey started off on the right foot with a birdie on 10 before running off three straight pars from No. 11. On the 14th hole, Casey drained an 18-foot birdie putt to get to 2-under for the round.

Following a pair of pars on 15 and 16, Casey went on a big run when he made five straight birdies from No. 17, putting him at minus-7. After exchanging a gain on No. 5 for his first and only bogey on No. 6, Casey made two more pars before closing things out with his ninth birdie on the par-5 ninth, giving him the clubhouse lead.

"I don't know what to say. I mean, I'm ecstatic," Casey said. "First, I'm loving being in Hawaii. I have not been here for a long time. The last time I was here was 2010 when I played in Maui, and it's just, it's great to be back. I've been in the Middle East for so long, and I chose to come over here. I had no idea what to expect today, so I'm over the moon with that."

Simpson, also playing the back nine first, played his first ever PGA Tour event with a short putter, having used a belly putter for more than 10 years. The change did not hinder Simpson at all as he got off to a quick start by making a 5-foot birdie putt on No. 10.

After a bogey on 12, Simpson ran off five straight pars from 13 before going on a huge run. In fact, Simpson used his hot putter to make eight birdies over his final 10 holes from 18, with the lone pars coming on Nos. 5 and 8. Simpson needed just 10 putts on the front nine, his back.

"Today was a big day for me," said Simpson. "It was one of my best putting rounds I've ever had to be honest ... I made a lot of putts. I didn't hit it great on the back nine, my first nine holes, but then started driving it well. If you drive it well around this golf course, you're going to give yourself opportunities."

Streb had an up-and-down front nine, which featured an eagle on No. 9, three birdies and two bogeys. On the back side, Streb made a trio of birdies from No. 10 to go along with another gain at the last to jump into a tie for second place.

Villegas did most of his work on the front nine with six birdies and three pars. It was a quiet back nine for Villegas as he wrapped eight pars around a birdie on the par-4 16th.

NOTES: A score of 62 is a career best for Simpson, who needed just 23 putts to complete his first round ... Streb already has a win and a total of four top-10 finishes in six events on tour this season ... Streb leads the tour with 108 birdies this season ... Geoff Ogilvy had a hole-in-one on the par-3 fourth hole.