Palm Harbor - American Ryan Moore birdied four of the last six holes to fire a four-under par 67 for a one-stroke lead after Saturday's third round of the $5.9 million PGA Valspar Championship.
Moore opened with 12 pars and shot one of only two bogey-free rounds surrendered Saturday by the Innisbrook resort's Copperhead course to stand on nine-under 204 after 54 holes.
Jordan Spieth, a 21-year-old American who shared second at last year's Masters, fired a 68 to stand second on 205 with compatriot Derek Ernst third on 206, American Sean O'Hair fourth on 207 and Swede Henrik Stenson joining the US duo of Matt Kuchar and Patrick Reed on 208.
Moore seeks his fifth US PGA triumph, the past two coming at the 2013 and 2014 CIMB Classic in Kuala Lumpur, Malaysia. He also won in 2012 at Las Vegas and took his first PGA title in 2009 at Greensboro, North Carolina.
Moore missed a four-foot birdie putt at the par-5 opening hole but saved par from 12 feet at the par-3 fourth and eight feet at the par-3 eighth.
"I just hit it closer," Moore said of his late birdie run. "I missed a lot of greens early, made a few chips and some great par savers. I made some good birdie chances from (13 on) and was able to hole them out."
Moore sank eight-foot birdie putts at the par-3 13th and par-5 14th holes, rolled in a birdie from 31 feet at 16 and closed with a five-foot birdie putt at 18 to seize sole possession of the lead.
"You just always have to be mindful on this course," Moore said. "You have to let it dictate what you do out there and that's how I've tried to play it."
Spieth seeks his third title in five months, although his only US PGA career title so far came at the 2013 John Deere Classic. Spieth won the Australian Open last November and followed up by winning the Hero World Challenge charity event hosted by Tiger Woods last December near Orlando.
Spieth opened with a tap-in birdie but took his lone bogey at the third, finding the left rough and a greenside bunker and missing a seven-foot par putt. He sank a seven-footer for birdie at the ninth and a 10-foot birdie putt at the par-5 11th, then birdied from 11 feet at the par-3 15th.
Spieth would become the youngest US PGA two-time winner since Spaniard Sergio Garcia in 2001.
Ernst's lone top-25 finish in 61 US PGA starts was a 2013 victory at Quail Hollow, when his par at the first playoff hole defeated England's David Lynn for the title. Ernst had been a fourth alternate and ranked 1,207th in the world at the time.
This week marks his first run of three sub-par rounds this season.
"I'm just going out there, taking it easy, trying to stay relaxed and having a great time," Ernst said.
Leading third-round scores Saturday in the US PGA Tour $5.9 million Valspar Championship (USA unless noted, par-71):
204 - Ryan Moore 69-68-67
205 - Jordan Spieth 70-67-68
206 - Derek Ernst 67-70-69
207 - Sean O'Hair 66-72-69
208 - Patrick Reed 72-68-68, Matt Kuchar 70-70-68, Henrik Stenson (SWE) 67-70-71
209 - Daniel Summerhays 70-72-67, Vijay Singh (FIJ) 69-70-70
210 - Russell Knox (SCO) 69-71-70, Billy Hurley 69-71-70, Nick Taylor (CAN) 70-70-70, Lucas Glover 69-69-72
211 - Sam Saunders 70-72-69, Chad Campbell 70-72-69, Luke Guthrie 68-73-70, Jason Kokrak 68-73-70, Brian Davis (ENG) 65-76-70, Shawn Stefani 68-72-71, Jason Bohn 70-69-72, Kevin Streelman 68-69-74, Brendon de Jonge (ZIM) 67-69-75
212 - Chesson Hadley 73-69-70, Francesco Molinari (ITA) 70-72-70, Danny Lee (NZL) 72-69-71, Jason Dufner 70-71-71, Lee Westwood (ENG) 71-70-71, Troy Merritt 72-69-71, Kenny Perry 69-72-71, Nick Watney 72-69-71, Charles Howell 70-70-72, Justin Thomas 67-72-73, Ricky Barnes 66-72-74