PGA Championship 2015 Leaderboard: Live Updates, Storylines to Watch for Friday

The PGA Championship may not have the luster of the Masters or the U.S. Open, but this year's tournament at Whistling Straits in Sheboygan, Wisconsin, could turn out to be the most exciting and dramatic of this year's major tournaments.

It certainly got off to a memorable start on Thursday, as Dustin Johnson shot a brilliant 66 to take a one-stroke lead into the second round.

Johnson played in the morning session in the opening round and was able to take advantage of favorable weather conditions. 

He is used to being successful in the early rounds of these competitions, averaging a 67.83 in the first two rounds of this year's four majors. However, that number increases to 72 over the final two rounds. He'll try to continue the first trend on Friday and reverse the second on Saturday and Sunday.

Rory McIlroy and Jordan Spieth were not as fortunate. The top two players in the world teed off in the afternoon and had to battle difficult winds throughout the round. Both players shot one under par at 71.

The second round will give McIlroy and Spieth the opportunity to play in the morning, while Johnson's tee time will be pushed to the afternoon.

McIlroy was one of the big stories heading into the tournament and throughout the first round as he returned from a ruptured ligament in his left ankle. The challenging Whistling Straits course could have caused problems for the long-hitting McIlroy, but he did not show any ill effects from the injury as he moved around the course with ease.

"

Roll up pant leg, get up and down for par. Watch Rory McIlroy's watery escape at No. 5: http://t.co/5eHPHBockH pic.twitter.com/gGV00SFQZN

— Golf Channel (@GolfChannel) August 13, 2015"

The question now is will he continue to show that he has overcome the injury or start to slow down in the later rounds of the tournament?

Brian Spurlock-USA TODAY Sports

McIlroy has no doubt that his ankle will pass the test. “I have full confidence,” McIlroy told the media after Thursday's round (h/t Brian Wacker, PGATour.com). “It doesn’t bother me one bit.”

Spieth did not appear to be on top of his game in the first round. He had a tendency to pull his drives to the left, and he also failed to convert a number of birdie opportunities throughout the round. However, he still managed to break par when he was not at his best.

"

He has an early start today. Can @JordanSpieth move his marker on Friday? @pgaofamerica @golfingindian Tee off @ 0805 pic.twitter.com/QSdGJXJSeM

— Anand Datla (@SportASmile) August 14, 2015"

That could be bad news for the rest of the field, as it seems likely that Spieth will find the form that allowed him to win the Masters and run away with the U.S. Open before long.

David Lingmerth was another huge story in the opening round, as he teed off in the afternoon and still managed to shoot a five-under 67.

While Lingmerth is not well known to casual golf fans, he ranks 21st in FedEx Cup points and is 45th overall in the world rankings. Lingmerth has a victory, a third-place finish and four top-10 finishes in PGA tournaments this season and has earned more than $2.5 million this year.

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.@dlingmerth mirrored his #BritishOpen start at #PGAChamp ... except he finished better: http://t.co/p3rkNCRsa3 pic.twitter.com/XkTm0nPima

— Golfweek Magazine (@GolfweekMag) August 14, 2015"

Jason Day fired a 68 on Thursday and he was one of the more prominent selections to contend in the PGA Championship prior to the start of the tournament. 

There's good reason for that, as he basically has no weaknesses in his game.

"

It's a major week? Oh, that must mean @JDayGolf is near the @PGAChampionship lead (via @BobHarig) http://t.co/tpN7HUJSii

— ESPN Golf (@ESPNGolf) August 13, 2015"

He's also been close so many times in the majors. He has finished in the top 10 nine times, though he has never won any of them. Day calls his previous majors learning experiences, with one of the most notable being this year's U.S. Open, when an attack of vertigo nearly prevented him from finishing the tournament.

Brian Spurlock-USA TODAY Sports

“I didn’t end up winning but I learned a lot,” Day told Gary Van Sickle of Golf.com. “I learned how far I could really push myself mentally and physically even though I felt like pulling out three times.”

If Day is finally going to break through in a major, he needs to have a strong second round that will put him in good position for Saturday's moving day round.