Kisner, the co-leader entering the day, holds a one-shot lead at 7-under 206.
Chris Stroud is trying to catch up to co-leaders Hideki Matsuyama and Kevin Kisner at the PGA Championship. Spieth then began to find his putting touch, making two birdies in a row from the eighth and three in a row from the 14th before a double-bogey at the last. "When we play at home, he shoots 65 all the time, " he said.
THE CHASER: Day hasn't won since The Players Championship last May, back when he was No. 1 in the world by such a margin that he stayed at the top of the ranking the rest of the year without winning.
Tiger Woods' record as the youngest player to complete a career Grand Slam of majors remains safe after Jordan Spieth handed in a 71, following three straight birdies on the back-nine with a scrappy double-bogey six at the last.
Kisner will have little room for error Sunday, and not just because of his slim advantage.
Quail Hollow has a history for rewarding golf's biggest hitters, but the 165-pound player who's been atop the leaderboard all week at the PGA Championship is accustomed to punching above his weight class.
Matsuyama's iron approaches simply weren't able to get the ball close to the hole, and the 12-footer he holed for par on No. 9 proved to be his longest make of the day.
In October 2003, at the Stonebridge Invitational at Stonebridge Country Club in McKinney, Stroud lost seven or eight balls during a practice round, but he told Lamar's coach, "Coach, this place is flawless for me".
"It played very hard today", the 35-year-old American said.
"I didn't make the putts I've been making the first two days and had just a awful finish there", said Kisner. "I know all these guys are going to be super nervous".
Kisner stood over his second shot on the 16 hole Saturday at 10-under par.
It was a round to forget for Jason Day after he carded an eight on the par-four 18th to fade from contention. Oosthuizen saved par from a similar spot Day was in on the 18th hole and shot 71.
Day won the PGA Championship two years ago, and after three consecutive birdies on the 14th, 15th and 16th, he collapsed.
It was a tough day for most of the players in Charlotte.
Grayson Murray is at 210 after shooting 69.
The final round will get underway at 8:05 a.m. ET, and here's a look at the tee times for the field.
Patrick Reed and Graham DeLaet, 2:15 p.m. But by the start of Saturday's third round at Quail Hollow Club his expectations had been lowered.
Kisner had the opportunity to take a larger lead into the final round until he was undone by Quail Hollow's demanding finishing stretch, known as the Green Mile. That should put him in a good state of mind for the final round.
Stroud, saying "I'm as calm as I've ever been", shocked himself to make the final group with a 71 despite a bogey-bogey finish.
Then one bad swing at the 16 bit Kisner like a rattlesnake.
PICK A WINNER: The winner of this tournament has come from the final pairing of the final round in 18 of the last 20 years. The pressure is likely to be too much for him.