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

After the best players in the world tore up Whistling Straits in near perfect scoring conditions on moving day, what will they do for an encore Sunday?

There was no rain and hardly any wind at the Kohler, Wisconsin, course, and Jason Day took advantage of those conditions to shoot a six-under 66, allowing him to take a two-stroke lead as he reached 15 under for the PGA Championship.

While Day played spectacularly throughout the round—and he was on fire throughout the back nine—he still has plenty of work to do if he wants to come away with the PGA Championship title.

"

Boom! What a great reaction. Jason Day pours in his eighth birdie of the day. #QuickHits http://t.co/uZX8lfbmSO

— PGA TOUR (@PGATOUR) August 16, 2015"

That's because Jordan Spieth is hot on his trail. Spieth was a stroke better than Day on Saturday, and his score of 65 allowed him to get to 13 under.

Spieth, of course, is going for his third major of the year. If he is able to overcome Day and the deficit he faces, he will arguably have one of the greatest seasons of any golfer.

Ben Hogan and Tiger Woods are the only golfers to win three majors in the same year. Hogan did not play in the PGA Championship in 1953 after winning the Masters, U.S. Open and British Open that year. In 2000, Woods finished fifth in the Masters before winning the other three majors.

Spieth would have a slight edge on Woods, because he finished fourth in the British Open, a tad better than Woods' Masters finish in his brilliant season.

"

If Jordan wins tomorrow, he'd become the only player EVER to win all 3 US majors in a season: http://t.co/QqWQOFBngA pic.twitter.com/9Vm0vXPXNm

— Golf Digest (@GolfDigest) August 16, 2015"

Day wants to do more than just keep Spieth from lifting the Wanamaker Trophy that goes to the PGA Championship winner. He wants to get rid of the label as the best player on the tour without a major championship.

Day has failed to bring home major titles when he's been close in the past.

"I'm not looking it as a negative," he said, per the Associated Press (h/t ESPN.com). "You can't, because you've got two shots and I've played phenomenal golf leading up to this. But now I've got to focus on Round 4. Everything I need to do is just make sure that I focus and prepare myself for tomorrow."

Brian Spurlock-USA TODAY Sports

In addition to the Spieth-Day duel, the final round could have huge implications for South African Branden Grace and Englishman Justin Rose. Both golfers are three strokes back of Day and will play in the penultimate pairing Sunday.

According to Justin Ray of the Golf Channel, if Rose can overcome the deficit, he will become the first English golfer to win the PGA Championship since Jim Barnes, who last accomplished the feat in 1919:

"

Justin Rose just 3 back. The only Englishman to win the #PGAChamp was Jim Barnes in 1916 & 1919 (1st 2 ever contested).

— Justin Ray (@JustinRayGC) August 16, 2015"

"

Branden Grace chips in for 64, Justin Rose lips out for eagle, Jason Day makes birdie to tie the lead. SO many things happening at once.

— Golf Digest (@GolfDigest) August 15, 2015"

Meanwhile, Martin Kaymer had a sizzling-hot performance Saturday, firing a seven-under 65. Kaymer, who won the 2010 PGA Championship at Whistling Straits in a playoff over Bubba Watson, is four strokes behind Day and clearly in contention.

"

Martin Kaymer began the final round of the 2010 PGA at Whistling Straits 4 off the lead. He will start Sunday 4 off the lead.

— Rex Hoggard (@RexHoggardGC) August 16, 2015"

The other key storyline Sunday may be the weather. After wind caused problems for golfers Thursday afternoon and rain caused a halt to Friday's second round, the players had perfect conditions Saturday.

The weather likely won't be perfect Sunday, as the winds are expected to pick up in the afternoon when the leaders tee off.

If the wind is a key factor, it favors the players who excel at the short game. This year, no player has been better in that area than Spieth, and it may be difficult to stop him as he pursues his third major of the year—and perhaps the greatest single golf season ever.