AUBURN, 19 Jul 2015 (AFP) - With temperatures hitting a high of 38 degrees Celsius (100 F) on the Grand National Golf Club course, players had trouble staying hydrated in the heat.
"It was hot. I must have gone through seven or eight bottles of water," said the 34-year-old Barnes.
Barnes and Piercy finished 54 holes at 13-under 200 and have a one shot lead over a group of five others, including Australian Mark Hensby, who is playing his first USPGA Tour tournament since 2013.
The two Americans stand atop a crowded leaderboard that includes 15 players within four strokes of first place. The logjam should make for another interesting Sunday shootout on the USPGA Tour which has seen its last three tournaments decided in a playoff.
Barnes, who has never won on the US Tour after a stellar amateur career that included winning the 2002 US Amateur Championship, sank three birdies on the first five holes and four more on the back nine.
"I've been playing some good rounds lately but not putting everything together," Barnes said.
"I found some good trigger points this week and they are working.
"I've been in this position before, but I just have to go out and play good golf the way I know I can and if it goes my way, great."
Piercy birdied four of the first five holes and also rolled in a three-foot birdie putt on the final hole to pull even with Barnes.
"I played great today even though I struggled a bit on the greens," said Piercy, a two-time winner on the USPGA Tour.
"I've won a couple of times and most of these guys haven't so I think that's an advantage, having gotten it done. My game feels good and I just have to finish it off."
Hensby followed up his sizzling 64 on Friday with a 68 in the third round and was one stroke back in a tie for third with Jason Gore, who shot 63, Will Wilcox, who sank a 61-foot eagle putt on the 16th hole en route to a 65, Emiliano Grillo of Argentina, who had a 67 and Kim Whee of South Korea, who came in at 68.
Hensby, of Melbourne, is playing in his first tournament since 2013 after undergoing two shoulder surgeries to fix an nagging injury from a 2006 car accident.
He got off to a slow start with two bogeys on his first five holes but then recovered with an eagle and three birdies on the back nine.
Leading scores after Saturday's third round of the US PGA Tour's Barbasol Championship (USA unless noted, par-71, a-denotes amateur):
200 - Ricky Barnes 67-68-65, Scott Piercy 69-66-65
201 - Jason Gore 65-73-63, Mark Hensby (AUS) 69-64-68, Will Wilcox 66-70-65, Emiliano Grillo (ARG) 68-66-67, Kim Whee (KOR) 67-66-68
203 - Johnson Wagner 69-68-66, Vaughn Taylor 71-69-63, Sam Saunders 64-70-69, a-Robby Shelton 68-69-66
204 - Boo Weekley 67-69-68, Alex Cejka (GER) 69-66-69, Andres Romero (ARG) 71-64-69, Kyle Stanley 70-67-67, Blayne Barber 69-67-68, Austin Cook 69-70-65
205 - Glen Day 72-63-70, Aaron Baddeley (AUS) 69-72-64, Ken Duke 68-68-69, Martin Piller 69-66-70