5 things we learned from Round 1 of the PGA Championship

The first round of the 2021 PGA Championship is in the books, and it certainly did not disappoint.

The Ocean Course at Kiawah Island lived up to its reputation as a difficult - but fair - major championship test. Corey Conners managed it best with his blistering 5-under 67, but plenty of golfers are within striking distance and have lots of time to make up ground.

Here's what we learned on Day 1 in South Carolina:

Kiawah is a ball-striker's paradise ...

Before the tournament started, few could agree on the type of golfer that would play well at Kiawah Island. Some argued its length would give a substantial advantage to bombers like Bryson DeChambeau and Rory McIlroy, while others believed the strong winds would afford short-game specialists like Jordan Spieth and Cam Smith a strong chance.

But the answer for who will succeed - at least after Round 1 - is clearly elite ball-strikers. Conners, Collin Morikawa, and Viktor Hovland all shot 2-under or better, and all three rank inside the top five in the field in strokes gained: ball-striking (off the tee plus approach) over the past 50 rounds. Even Keegan Bradley (3-under) ranks seventh in that regard.

Brooks Koepka, Will Zalatoris, Joaquin Niemann, Paul Casey, Cam Davis, and Tyrrell Hatton are all top 25 in the aforementioned stat, and all of them sit at 1-under or better through 18 holes.

... But anyone can contend

With all of that said, the top of the leaderboard does have some outliers, meaning there are other ways to score well at the tough Pete Dye layout.

Phil Mickelson might be the most notable name near the top who doesn't fit the ball-striker mold. He only hit 10 of 18 greens in regulation but still managed to post a 2-under score.

Branden Grace and Martin Laird also shot 2-under, and even European Ryder Cup captain Padraig Harrington carded 1-under. None of those three players are known for their ball-striking prowess.

Koepka still shows up for majors

Well, well, well - look who's in contention at another major championship.

"It's a major. I'm going to show up," Koepka said after his opening round, according to ASAP Sports. "I'm ready to play. I've been itching to do this since Augusta. I mean, I feel so much better now. I don't need to be 100% to be able to play good."

Koepka carded a 69 on Thursday morning to share the clubhouse lead for most of the day. He's coming off back-to-back missed cuts, including one at the Masters. But his knee appears to be in better shape than it was at Augusta in April - and it seems the Koepka who's won four major titles is in attendance at Kiawah Island.

Here are the best cumulative scores to par in majors since 2017:

Brooks Koepka: 81-under
Dustin Johnson: 27-under
Hideki Matsuyama: 25-under
Xander Schauffele: 25-under

1st rounds remain McIlroy's Kryptonite

The win at Quail Hollow two weeks ago did not cure McIlroy's first-round struggles in major championships.

The two-time PGA champion shot 75 and finds himself in a tie for 78th after Day 1. He started his day with a drive that ended up in the penalty hazard, and he had to work hard just to make bogey. He went on to bogey three of Kiawah's four par 5s.

McIlroy faces a steep uphill climb to make the cut at the venue where he won by eight strokes in 2012.

Pros will always find an edge

The par-4 18th at Kiawah Island is a beast of a golf hole. It typically plays into the wind and is listed at 505 yards in length - with trouble all down the right side. But the best players in the world may have found a way to make it much easier.

How? By hitting it without fear, knowing there are grandstands down the left side that will catch any errant tee shots. The reward for hitting it way left was a free drop with a good lie and an ideal angle into the green.

Koepka was the first to take advantage of the free drop.

Bradley, who also hit it left, called the grandstands' presence "comforting" and advised spectators to take cover.

Though this unconventional approach might seem like a minor detail on Thursday, keep it in mind on Sunday when the leaders begin to make their way through the closing holes. Hopefully, the grandstands won't determine who hoists the Wanamaker Trophy.