ORLANDO, 21 Mar 2015 (AFP) - Stenson sank a 13-foot birdie putt at 15, eagled the par-5 16th with a 20-foot putt and dropped his approach inches from the cup at 18 for a tap-in birdie to finish a six-under par 66 and stand on 16-under 200 at the $6.3 million US PGA Tour event.
"Pretty nice way to finish," Stenson said. "What I've done has put me in a nice position but it has got to be done all over again tomorrow. I've got to go out there and keep the same mindset."
It was the second day in a row Stenson went four-under over the final four holes. He matched the low 54-hole total at Bay Hill first recorded by Andy Bean in 1981.
"I just hit some great shots two days in a row," Stenson said. "You're going to pick up some shots if you go 4-under two days in a row on the last four."
American Morgan Hoffmann, who led after the first and second rounds in quest of his first tour title, fired a 71 to stand second on 202, one stroke ahead of Australian Matt Jones and Americans Jason Kokrak, Ben Martin and defending champion Matt Every.
Stenson, trying to snap a run of eight US PGA losses by 54-hole leaders, knows the layout well, living in the area, and his bogey-free round also featured birdies at the par-5 sixth and par-4 ninth holes.
World number one McIlroy, who could win his third major title in a row and complete a career grand slam with a victory in next month's Masters, pulled within one shot of the lead with back-to-back birdies only to bogey the next three holes.
McIlroy had a tap-in birdie at the par-5 sixth and chipped in a 22-footer from just off the green for birdie at the ninth. After birdies at 12 and 13, he was just one adrift.
But McIlroy's charge collapsed. He missed a 10-foot par putt at the par-3 14th and a three-foot par putt at 15, then went into a fairway bunker and missed a seven-foot par putt at 16 for his third bogey in a row. He fired a 71 to stand seven behind Stenson.
Jones, who defends his lone US PGA title in two weeks at the Houston Open, closed with four birdies in a row, including a 75-footer at the par-3 17th.
It was a historic day of shotmaking at Bay Hill as Daniel Berger made the first albatross in tournament history at the par-5 sixth, the American holing out from the fairway with a stunning 237-yard shot on his way to shooting 68.
Thailand's Kiradech Aphibarnrat matched the tournament record for the low front nine score with a 30 on his way to a bogey-free 65. Kiradech made six birdies in the first nine holes and needed only nine putts on the first nine holes.
After dropping his approach at the first inches from the cup on the way to a birdie and adding a 15-foot birdie putt at the third, Kiradech ran off three birdies in a row starting at the fifth, the first of them the longest putt at 14 feet. At the ninth he sank a 13-foot birdie putt to equal to record.
On his back nine, Kiradech fired eight pars and birdied the par-5 16th.
"I'm striking the ball really well," said Kiradech, who said the key to his low score was avoiding mistakes.
"I made eight birdies in the first round, but just had a two-under finish. But today I had a low score because I didn't drop any shots."
Kiradech said he's hoping his renewed confidence will help him get to the next level.
"I've been playing last year a lot in the States. I made cuts, but couldn't finish high," said the Thai, although he added that his immediate goal for the weekend is just to keep things going as they are.
"Tomorrow I don't want to force myself," he said, "just play my game."
Leading scores after Saturday's third round of the $6.3 million US PGA Tour Arnold Palmer Invitational (USA unless noted, par-72):
200 - Henrik Stenson (SWE) 68-66-66
202 - Morgan Hoffmann 66-65-71
203 - Jason Kokrak 67-71-65, Matt Jones (AUS) 71-65-67, Ben Martin 68-67-68, Matt Every 68-66-69
205 - Sean O'Hair 69-68-68
206 - Kiradech Aphibarnrat (THA) 70-71-65, Brendan Steele 71-67-68, Kevin Na 67-70-69, Harris English 68-66-72
207 - DA Points 70-70-67, Keegan Bradley 68-70-69, Louis Oosthuizen (RSA) 69-68-70, Rory McIlroy (NIR) 70-66-71, Danny Lee (NZL) 72-64-71
208 - Brandt Snedeker 68-74-66, Sam Saunders 70-71-67, Camilo Villegas (COL) 69-72-67, Ryo Ishikawa (JPN) 70-69-69, John Peterson 67-71-70, Ian Poulter (ENG) 67-70-71
209 - Russell Knox (SCO) 74-68-67, Hudson Swafford 75-66-68, Daniel Berger 73-68-68, Kevin Kisner 69-71-69, Charles Howell 71-68-70, David Lingmerth (SWE) 69-67-73