Glover posted a 66 or lower for the sixth time in his last seven rounds – three of those came last week when he won the Wyndham Championship to go from No.112 in the FedEx Cup and well into the top 70, who reach the PGA Tour's post-season.

Fellow American Taylor Moore (65), who won his first PGA Tour title earlier this year at the Valspar Championship, bogeyed his last hole at TPC Southwind to trail Glover by one.

After rounds of 66 and 67, Sydney’s Cam Davis had a 69 to sit at eight under and tied for 12th, while compatriot Jason Day (72) is two over.

Davis' mixed round included four bogeys, three birdies and an eagle on the par-5 16th to keep him in sight of just a second tour victory.

“It was a bit of a grind today,” Davis said. “I didn't quite have my stuff off the tee, which made it a lot more difficult trying to get the ball on the green in regulation.

“Hung in there well, had a little stretch on the back nine to get myself back sort of in it, and yeah, still a chance to get to next week with a good round tomorrow.”

England's Tommy Fleetwood had a 66 to be two off the pace, as he goes after his first win on American soil.

Max Homa ran off three straight birdies on the back nine for a 65, while Jordan Spieth had to settle for a 68. They were both three back at 11 under.

Rory McIlroy (68) and Patrick Cantlay (66) were among those five shots behind.

Lucas Glover is a riding a massive wave of good form. PHOTO: Getty Images.

Glover, who chipped in for birdie on the opening hole and made an 18-foot birdie putt look easy on the next, had only one wobble. He missed the 5th green to the right in clumpy, wet grass and couldn't get his recovery close enough for par.

"I'm in a good spot. Just iron a few things out and wake up tomorrow a little more confident than I am right now and see where we are," Glover said.

"Three months ago, if I'd have been mad at 66 or if you told me I'd be mad at 66, I'd say you were crazy."

The 43-year-old former U.S Open champion has now shot in the 60s in 20 of his last 21 rounds and his confidence is soaring.

He is No.49 in the FedEx Cup. The top 50 advance to the BMW Championship next week, but the playoff opener is a chance to secure a spot in the top 30 for the Tour Championship.

Moore birdied three of the par 3s and was tied for the lead on two occasions on the back nine until poor drives led to bogeys.

Fleetwood had three birdies over his last five holes. Homa didn't made a birdie until the ninth hole, and then felt as though he couldn't miss. He ran off three straight birdies late in his round and shot 31 on the back.

Spieth stayed close with a pair of birdies early on the back nine and had plenty of other putts burn the edge. He began the post-season at No.31 and has plenty at stake on Sunday, for the FedEx Cup and possibly securing one of the six automatic spots for the Ryder Cup.