(Reuters) - American Russell Henley took the lead but Rory McIlroy loomed large, just two strokes behind after the third round at the $8 million Deutsche Bank Championship in Norton, Massachusetts on Sunday.
Henley dominated the par-threes to card a six-under-par 65 and jump to the front at 12-under 201 on a day of low scoring in ideal conditions at the TPC Boston.
He edged one shot ahead of compatriot Billy Horschel (67), while world number one McIlroy made his presence felt with a sizzling 64 to join Australian Jason Day (69) and American Chris Kirk (64) in a tie for third at 10-under.
Northern Irishman McIlroy, seeking his fourth PGA Tour victory in five starts, almost holed out at the 15th and 16th holes, tapping in from inside a foot both times.
McIlroy, whose sizzling summer stretch has included major victories at the British Open and PGA Championship, was clearly back to his best after an average performance last week when he tied for 22nd in the opener of the PGA Tour's lucrative four-event FedExCup playoff series.
Powering his drives well over 300 yards and taking dead aim at pin after pin, McIlroy compiled seven birdies to match the best round of the day.
"I hit a lot of iron shots close, put myself in position to do that, more so than the first couple of days (when) I didn't hole anything," McIlroy told NBC television after lipping out with a 10-foot birdie putt at the last.
Henley was also on his game, particularly on the par-threes where he picked up three of his seven birdies.
The 25-year-old has recorded two PGA Tour victories, most recently at the Honda Classic in March when he beat McIlroy and two others in a playoff.
His form has since tailed off – no top-25 finishes in his past nine starts – but he says an improved attitude has helped him this week.
"Any day you shoot 65 is a pretty good day," said Henley, who is 62nd in the FedEx Cup standings.
"When you're making putts and hitting it well, golf is a lot of fun. It's such a tough game and we put so much pressure on ourselves out here and I'm just trying to have a good attitude this week."
Day, meanwhile, started strongly to take the sole lead with three birdies in the first seven holes and was playing so well he looked capable of running away with it.
However, he made heavy weather of the back nine, running up successive bogeys at the 14th and 15th holes.
"When I made that (first) bogey it was pretty surprising, because it was such an easy up-and-down," lamented Day, the world number seven who is playing his way back into form after a season interrupted by a thumb injury.
"And then I hooked my tee shot on the next hole. I played so good and yet didn't shoot the score I expected."
American Patrick Reed carded a shocking 82 to miss the 54-hole cut after starting the day only two strokes off the lead.
Reed made four double-bogeys in a five-hole stretch starting at the 10th.
The top 70 players on the FedExCup points list after the Deutsche Bank Championship advance to next week's BMW Championship in Englewood, Colorado where the leading 30 will qualify for the Sep. 11-14 Tour Championship finale in Atlanta.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Mark Lamport-Stokes)