PONTE VEDRA BEACH, Fla. — Dustin Johnson made it clear that he likes being the No. 1 ranked player in the world, and he played like it in Thursday’s opening round of the Players Championship at TPC Sawgrass.

Johnson, who’s been ranked No. 1 in the world for the past 15 months, played himself into a share of the lead with Webb Simpson, Alex Noren, Chesson Hadley, Patrick Cantlay and Matt Kuchar with a 6-under-par 66.

The Players Championship is the only PGA Tour event Johnson has played more than three times and never finished in the top 10 (he’s 0-for-9).

So, where did that round come from — particularly because he’s played only once since the Masters last month?

“Yeah, I’m definitely surprised, but I think a lot of it has to do with putting,’’ Johnson said. “I don’t think I putted very well around here as a whole. I think I just struggled on the greens here. They’re tough. I feel like they’re tough to read. But today I felt like I did a very good job reading the greens.

“I haven’t had the best record here, but it’s a golf course that I like, I enjoy playing and I feel like I should play well here.’’

Johnson, who has Justin Thomas, Jon Rahm, Jordan Spieth and Justin Rose right behind him in the world rankings, knows he’s going to have to play well to retain his top ranking because all four can overtake him this week.

“Every week Justin’s pretty close,’’ Johnson said. “He’s been pretty close to me for awhile, so I mean every week I know there’s a chance that someone can pass me. I definitely want to stay there, but if someone passes me, it’s not going to change anything, I’m going to still go back to next week and try to get it back.

“Obviously, this week if I play really well I’ll still be No. 1. If I don’t, someone’s going to pass me, which is OK.’’

Johnson, who elevated to No. 1 when he won last year’s Genesis Open at Riviera, said “it was definitely a big deal to get’’ to No. 1 and, he added, “It’s a big deal to stay there. I mean, I like being No. 1, so I want to stay there.’’

Interestingly, before the tournament, Johnson’s swing coach, Butch Harmon, told the Golf Channel he believes Johnson needs to work harder.

Asked for a response, Johnson said, “I work as hard as I want to and I feel like I work pretty hard. I don’t want to wear myself out.’’

As surprising as Johnson’s 66 was how badly Spieth and Thomas struggled. Spieth, who’s missed the Players cut the past three years, shot a volatile 3-over 75 and Thomas shot a 1-over 73. The third player in that marquee group, Rory McIlroy, shot a 1-under 71.

McIlroy said he was impressed with how Johnson has maintained the No. 1 ranking.

“I mean I think he’s done a great job because I feel it’s harder to stay there than it is to get there,’’ McIlroy, a former No. 1, said. “I think that once you’re there, you have a lot of points to defend and there’s a lot of that that goes into it. There shouldn’t be added pressure — obviously Dustin doesn’t look like he feels anything on the golf course, so I don’t think pressure really gets to him — but maybe an expectation with being the world No. 1 than there is if you’re not.

“So I think the impressive thing is staying there for as long as he has. Obviously a lot of guys, he hasn’t played the last few weeks, so a lot of guys have a chance now to sort of take it from him.’’

Behind Johnson and the other leaders is a group of six at 5-under, including Jhonattan Vegas, defending-champion Si Woo Kim, Rory Sabbatini, Andrew Landry, 52-year-old Steve Stricker and Keith Mitchell, a PGA Tour rookie who got into the field as an alternate late Wednesday when Paul Casey withdrew.

“I don’t want to say it was a surprise, because I’ve been playing well lately,’’ Mitchell said. “I was surprised to be able to play, first of all, so that was more of the surprise, just to be able to tee it up. When we did, we just tried to take advantage of our opportunity.’’

Reigning US Open champion Brooks Koepka reinjured his left wrist while practicing Wednesday, but he played Thursday and shot a 2-under 70.

Koepka, who only recently returned after being out for months with the injury, hurt it when a maintenance person in a golf cart drove right in front of him in midswing while he was hitting balls at the range.

“We were on the back of the range hitting punch-stinger 3-irons, kind of practicing for 18, and this guy drives his cart right across in front of me,’’ Koepka said. “I mean, I unloaded everything [in the swing]. There were a bunch of guys that were around that said, ‘Holy [bleep], I can’t believe you actually stopped that.’

“It was the first time my strength actually backfired, being strong enough to actually stop it. The guy on the cart was about 15 yards away, if that. He would have been dead. It was perfect timing.’’

Koepka, who said he had his hand in ice all Wednesday night, was asked why he didn’t withdraw.

“Because I fought through the [injury] for three months, and I’m just not going to quit,’’ he said. “When I went to the first tee, I still felt like I can win the golf tournament. If I don’t feel like I can win I won’t tee it up. I don’t quit, man.’’