Jordan Spieth 6-under through 36 holes at the PGA Championship

Jordan Spieth is in the hunt.

With five birdies down the stretch, Spieth finished his Friday round at the PGA Championship at 6-under and just a shot off the provisional lead established by David Lingmerth.

He kicked his round into high gear when approaching the turn, sinking a difficult sand shot from below the green and turning a likely bogey into a scoring hole.

"If there was a spark it was definitely on 18," Spieth, who played the back nine first, said after the round. "Arguably the best one of the year."

He rallied off three more on a clean second nine, rarely finding himself in any difficulty.

Spieth will be a handful of shots off the lead when he begins in the third round, but the quick study is building up to tournament contention, like he's done so effectively in the past.

The American Slam awaits.

Spieth's Round

17 - Hole 8 (Par 4, 507 yards)

• Spieth misses a 27-foot putt for the outright lead. (-6)

16 - Hole 7 (Par 3, 221 yards)

• Spieth finds the edge of the green with his tee shot. Needs two putts to sink it after narrowly missing right edge. (-6)

15 - Hole 6 (Par 4, 355 yards)

• After putting himself in a tough spot short, attempting to drive the green, Spieth knocks his second shot in tight and grabs a share of the tournament lead. (-6)

14 - Hole 5 (Par 5, 603 yards)

• Three shots needed to reach the green. He slides his birdie attempt under the hole left. (-5)

13 - Hole 4 (Par 4, 489 yards)

• Spieth travels a long lag putt to within a few inches after leaving his second shot short. (-5)

12 - Hole 3 (Par 3, 181 yards)

• Spieth finds slope McIlroy doesn't. He drills a fifth birdie for his round after carrying a near-perfect tee shot to five feet. (-5)

11 - Hole 2 (Par 5, 593 yards)

• Poor tee shot keeps Spieth short of the green after three shots, but he's able to knock in a short putt for par. (-4)

10 - Hole 1 (Par 4, 408 yards)

• Spieth hits a mid-range birdie try dead on after two strong golf shots. He now has three birdies in his last four holes. (-4)

9 - Hole 18 (Par 4, 520 yards)

• Misses badly right with his approach shot, landing in a nasty bunker, but flips an incredible sand shot that turns, landing softly into the cup. (-3)

8 - Hole 17 (Par 3, 223 yards)

• Spieth drops a 231-yard seven iron that rolls to 16 feet past the hole. He slides the birdie putt to the right, settling for par. (-2)

7 - Hole 16 (Par 5, 569 yards)

• It's a tap-in birdie on 7 after he spins a beautiful touch wedge from the thick rough just off the green after reaching it in two shots. (-2)

6 - Hole 15 (Par 4, 518 yards)

• Spieth hits the fairway and lands on the green with his approach, but fails to knock down his birdie putt from outside McIlroy and Johnson. (-1)

5 - Hole 14 (Par 4, 397 yards)

• Sticks approach setting up an 11-foot birdie opportunity, misses it left. Knocks down three-footer for par. (-1)

4 - Hole 13 (Par 4, 404 yards)

• First two shots both find rough. Sticks birdie chip within a couple feet and taps in for par. (-1)

3 - Hole 12 (Par 3, 143 yards)

• Finds greenside bunker off the tee. Chips second shot over the green. Knocks third shot within three feet. Makes bogey. (-1)

2 - Hole 11 (Par 5, 563 yards)

• Approach shot finds rough just left of the green, third shot skips over the hole. Makes 18-foot birdie putt (-2)

1 - Hole 10 (Par 4, 361 yards)

• Green in two, 26-foot birdie putt rolls past the hole. Saves par from three feet. (-1)