PGA Championship 2015: Leaderboard Scores and Highlights from Saturday

Jason Day took a big step toward collecting the first major championship of his career Saturday. The 27-year-old owns the 54-hole lead in the 2015 PGA Championship at Whistling Straits in Haven, Wisconsin.

At 15 under, Day is two shots ahead of second-place Jordan Spieth:

Few stars have been closer to winning a major without actually taking one than Day. In six years, he has three runner-up finishes and nine top-10s, but no victories.

He believes self-conviction is the biggest key to finally turning his luck around, as he told Alan Shipnuck of Golf.com:

"

"The last bit of the puzzle is all up here," he says, pointing at his noggin. "Having the belief and confidence that you can do the stuff that other guys do on Sundays. I mean, that's really inside your head. And it's just amazing how the more and more I stay out here over the years, the more it's all about the head, rather than the whole game itself."

"

After his back nine in the third round, it looks as though Day has passed all the mental hurdles required to win a major. He played his best golf between the ninth and 14th holes, gaining six strokes in the process with four birdies and an eagle.

ESPN.com's Jason Sobel attempted to put Day's marvelous stretch into perspective:

Day opened the door a bit for the rest of the field with a double bogey on 15 but rebounded with a birdie on 17.

Regardless of how well he played, Day might be fighting a losing battle against the force of nature that is Spieth.

The reigning Masters and U.S. Open champion closed his third round with an incredible six-under 30 on the back nine. As a result, he moved to 13-under for the tournament and into second place. The PGA Championship couldn't have said it better with this tweet:

No matter where Spieth finishes in the PGA Championship, his 2015 season has been something special. Only Tiger Woods has posted a lower overall score at the four major tournaments in a single year, per Golf Channel researcher Justin Ray:

And Spieth still has more time to eclipse Woods' mark.

There's almost an air of inevitability about the tournament after Spieth's marvelous third round. The 22-year-old is the best golfer in the world, riding a wave of momentum not seen since Woods' prime.

Spieth may not be the leader heading into the final round, but he's likely the consensus favorite to win.

Looking a little further down the leaderboard, nobody did more to put himself into contention on Saturday than Branden Grace, who shot an eight-under 64 in the third round. He also had one of the best shots of the day, somehow navigating his way through this brutal bunker on No. 18:

Along with Grace, Martin Kaymer was one of Saturday's biggest risers. The 30-year-old closed his third round with an impressive five-under across the back nine to finish at seven under for the day. Consistency was the key for Kaymer as he reached 10 of the 14 fairways off the tee and 15 of 18 greens in regulation.

Along with that consistency, Kaymer demonstrated an ability to pull a rabbit out of his hat on occasion, such as these birdie putts on Nos. 12 and 17:

Throughout his career, the two-time major champion has often flown under the radar, getting overshadowed by the younger generation of stars. Should he pull off the win Sunday, he'd enter rarefied air, per Ray:

Given the number of talented golfers ahead of the fifth-place Kaymer, a third major title might be a bridge too far.

Sunday should make for great theater. A head-to-head battle between Day and Spieth is the kind of thing fans expect to see in the final round of a major tournament.

Green Bay Packers quarterback Aaron Rodgers is looking forward to the action:

It would be great to see Day capture his first major, just as it would be great to see Spieth win all three of the American majors in the same season.

And don't count out the likes of Kaymer, Grace and Justin Rose, all of whom have a legitimate chance of being the last man standing at the end of play Sunday.

With so many guys still in the mix, you couldn't have envisioned a better finish for the final major of 2015.