Matthew Fitzpatrick and Webb Simpson shot opening-round 66s on Thursday to share the lead at 6-under par after the first round of the World Golf Championships - Workday Championship at The Concession in Bradenton, Fla.

They hold a one-shot lead over Billy Horschel, Kevin Kisner, Brooks Koepka andSergio Garcia. A group of six players another shot off the pace includes world No. 2 Jon Rahm and Tony Finau, who lost in a playoff last week at the Genesis Invitational.

The Concession, designed by Jack Nicklaus and Tony Jacklin, is hosting its first PGA Tour event after the WGC was moved from Mexico last month due to challenges related to COVID-19.

While 18 players shot in the 60s, The Concession got the better of several marquee players.

Top-ranked Dustin Johnson is tied for 64th at 5 over along with Bryson DeChambeau, while Matthew Wolff is last in the field after carding an 83. Beginning his day on the back side of the course, Wolff's front nine included a rarity as he carded a 3, 4, 5, 6, 7 and an 8 in a six-hole stretch between the 11th and 16th holes.

The leaders encountered no such struggles as Fitzpatrick had five birdies on his bogey-free card. Simpson offset a bogey on No. 5 with six birdies.

Simpson said he spent more time than normal plotting his strategy for a new course -- which is known for its contoured greens.

"We go to some of these courses and we don't even talk about anything because we know where to hit it, we know where to miss it," he said. "Here we say every tee shot, if we're downwind, what are we doing? If we're into the wind, what are we doing?"

Northern Ireland's Rory McIlroy is in a group of six players three shots off the lead at 3 under. He left several putts short on Thursday while carding six birdies against a trio of bogeys.

McIlroy said he first laid eyes on The Concession on Tuesday, while Koepka said Thursday was the first time he had played the back nine, where he shot a 1-under 35.

"I holed some good (putts), but then I missed some that I should have made," McIlroy said. "I don't feel like I made bad strokes. Might have been a couple of misreads and putts that I felt that I hit good that just didn't do what I thought they were going to do.

"I'll go do some work here in a little bit and try to get it figured out for tomorrow."

Finau finds himself in contention again after losing in Sunday's playoff to Max Homa. His lone PGA Tour victory came in 2016 at the Puerto Rico Open, an opposite-field event going on this week.

Finau was able to get in the clubhouse with a 68 despite having his approach shot on 17 ricochet off a sprinkler head and his drive on 18 roll into an unplayable lie. He scrambled to make par on 18 to save his 4-under round.

"I had a really tough break on 17, hit a second shot where you kind of have to miss it, I kind of bailed out to the right a little bit, ended up hitting a sprinkler head and almost jumping out off the course," he said. "That would have been real bitter if I made bogey on 18 after coming close to hitting that fairway, too.

"Yeah, you feel great whenever you make a putt on your last hole."

NOTES: Patrick Cantlay withdrew before the first round due to a stomach ache and dehydration. ... DeChambeau won the 2015 NCAA Division I Men's Championship at The Concession. ... The course was named after the putt Nicklaus famously conceded to Jacklin in the 1969 Ryder Cup as their match ended up in a tie. ... This is the first WGC event of the season following the cancellation of the 2020 HSBC Champions. ... Johnson's six WGC titles are second only to Tiger Woods' 18.