World No. 1 Scottie Scheffler conjured a late birdie blitz to fire a four-under-par 68 and grab a one-shot lead after the third round at the PGA Tour's Memorial Tournament in Dublin, Ohio on Saturday.

Scheffler, bidding to successfully defend his crown at Muirfield Village, rattled in four birdies in the final five holes to drop to eight under, one ahead of overnight leader Ben Griffin, who stumbled with an even-par 72.

"I don't know what the scoring average was today, but I was definitely proud of the way I finished and it was really challenging," Scheffler said afterward.

"Through 13 holes I felt like I was playing really good and I was only even par. Just a hard golf course."

Three-time major champion Scheffler, who started the day three off the pace, was forced to bide his time after opening his round with 13 pars.

But the 28-year-old American got things going on the par-four 14th, draining a 10-foot birdie putt before making a birdie four on the par-five 15th, when his third shot from the edge of the green left him with a tap-in.

A par on 16 left him at two under for the day but Scheffler was soon on the move at the par-four 17th, when he stuck his approach to eight feet and then rolled in the birdie putt.

Another birdie on the 18th, with Scheffler draining a 14-foot birdie putt, thrust him into a share of the lead alongside Griffin.

At that stage, Griffin looked to have overcome the worst of a roller coaster round to hang on to the lead.

The in-form American, chasing his third PGA Tour win of the year, had got off to a smooth start after a trio of early birdies on the sixth, seventh and eighth holes.

But four straight bogeys derailed his progress and allowed the chasing pack to close.

Griffin steadied the ship with back-to-back birdies on 14 and 15 leaving him on 10 under, five clear of the field.

Yet Scheffler's late charge narrowed the deficit and ensured Griffin headed to the 18th with a share of the lead.

He looked to have done enough to finish the day alongside Scheffler when his third shot from the greenside rough left him with a five-footer to par.

But Griffin's short putt rolled wide for bogey, leaving him with the daunting task of having to chase Scheffler in Sunday's final round.

"I felt like I was starting to separate myself midway through and then kind of got to some tough holes and didn't execute very well," Griffin said.

"You can do that out here. Tomorrow I've got to clean up some of those holes, make sure I stay aggressive."

Scheffler, meanwhile, said he had not panicked after seeing Griffin go five shots clear at 10 under earlier in the round.