IRVING, Texas — Jordan Spieth finally felt like a kid teeing it up against the big boys on the PGA Tour.

The golf part wasn't what troubled the 16-year-old high school junior.

His dilemma was whether to call Tom Pernice Jr., his 50-year-old playing partner, "Mr. Pernice" or "Tom."

While Spieth never actually figured that out — alternating between the two, then avoiding it — he continued to defy the expectations of everyone but himself, shooting a 3-under 67 yesterday to move solidly into contention entering the final round of the Byron Nelson Championship.

Spieth's best round yet left him tied for seventh, six shots behind leader Jason Day, and injects all kinds of intrigue into an event that was thought to be missing an attention-grabbing headliner.

"I know the pins are going to be the toughest pins I've ever experienced in my life, but I'm confident," said Spieth, who just last week was competing in a high school state tournament (which he won). "I'm going to start firing because I got nothing to lose, nothing to hold back."

Day shot a 3-under 67 yesterday to pull into the lead by himself. He was part of a seven-way tie after the first round, then was a stroke behind after the second round.

A win would be the first of his promising career. Considering he's 22, that would normally be a big deal; this week, it almost seems old.

Day actually is a fitting foil to Spieth-mania. Three years ago, he won a Nationwide Tour title, making him the youngest winner of a PGA Tour-sanctioned event. His best finish in a PGA event is second in 65 events.

"Certainly it's playing on my mind a little bit, my first big-time chance," said Day, an Australian who lives in Fort Worth.

Second round co-leader Blake Adams shot even-par 70 and is two strokes back.

ELSEWHERE

Wood leads BMW: England's Chris Wood shot a 4-under 67 for a 205 total and holds a two-stroke lead over Robert Karlsson, who had a course-record 62 in the third round of the BMW PGA Championship at Wentworth, England.

Karlsson finished at 6-under 207 and tied with Danny Willett (70) despite a quick turnaround from his home in Monaco after he thought he'd missed the cut on Friday. Karlsson flew home to Monaco on Friday before receiving a phone call saying he was playing on the weekend. He flew to Paris, slept for two hours, then paid $11,000 for a private jet to take him to London, arriving at the course an hour before tee time.

Riegger sits on five-shot cushion: John Riegger shot an 8-under 63 to take a five-shot lead after the third round of the Rex Hospital Open, while high school sophomore Grayson Murray fell off the pace at the Nationwide Tour event in Raleigh, N.C.

The 16-year-old Murray shot a 1-over 72 and is at 2 under for the tournament. Riegger is at 20-under 193. Chris Nallen, who shot a 66, is in second place, five behind at TPC Wakefield Plantation.