Koepka, who had missed cuts in two of his previous three tournaments, said his performance was thanks to the work he had put in. "Sometimes you've got to take that step back to take two steps forward", said Fowler. "I'm looking for that next step".
A host of major winners were then queueing up to mount a final-round challenge, with Brooks Koepka fourth on nine under, Justin Thomas a shot further back, and Phil Mickelson and Louis Oosthuizen on seven under, along with Chez Reavie and England's Matt Fitzpatrick. "I wouldn't worry. I've got 36 holes to go, man, I ain't anxious".
Fourth-ranked Webb Simpson, another two-time victor this season, totaled 66 with four birdies on the back nine and is six strokes down in a tie for eighth with Jason Day of Australia, who had a 67, Louis Oosthuizen of South Africa, who also shot 67, and Sungjae Im of South Korea, who came in at 68.
Byeong Hun An of South Korea, who made four straight birdies on the back nine, finished with a 66 and was alone in second place.
Dustin Johnson, Danny Willett and Henrik Stenson all shot one under par, with new world number one Jon Rahm returning a level-par 70 containing four birdies and four bogeys. Todd hit a 6-iron to the left side of the green, and he had to roll the ball over a mound breaking left at least 5 feet.
"I'm excited to be in this position and feel like if I can go out there and swing a little better and keep this putting momentum going, I'll be in good shape", Todd said.
"I just focused all on speed", statedTodd "It happened to just drift right there in the middle of the hole. Bonus birdie there, but that's what you've got to do to win golf tournaments".
He blasted out and sank a 16-foot birdie putt only to bogey 17 and miss a seven-foot birdie putt ahead of parring the last.
The 35-year-old American, who converted an impressive 50-foot birdie putt over a slope at the par-three 14th, walked off the course feeling better than ever heading into the weekend.
Rickie Fowler (69) ended the day two back from the lead after a pair of bogeys on the back nine dented an otherwise clean round. He hit his second shot from 190 yards to 9 feet and made the putt for birdie.
"It's been nice to see some putts go in", Fowler said. That's why I think him and Butch (Harmon) are way different than any other coach, they know exactly the right thing to say, when to jump on you, when to kind of lay off.
But he reacted with a great pitch-and-putt for birdie at the long 16 th and two excellent closing pars kept him at one under together with Tommy Fleetwood, who supplied among the highlights of the round when he holed out from simply over 100 lawns for an ending up birdie at the 18 th after his drive plugged in a bunker.