Jason Day will take a two shot lead into the final round of the US PGA Championship but he will have to hold off a strong chasing pack to claim a first Major Championship.
The Australian carded an eagle, eight birdies, two bogeys and a double in a dramatic third round 66 which took him to 15 under but was outdone by Jordan Spieth who came home in 30 to register a 65.
Masters Tournament and US Open champion Spieth is aiming to become just the third man in history to win three Majors in the same year and will go out in the final group on Sunday with Day.
Justin Rose is a further shot back after a 68 and sits alongside Branden Grace whose 64 was the low round of the day.
Day has finished in the top ten in six of the last 11 Majors and is confident he has what it takes to get over the line this time.
"I played great all three rounds and I've just got to keep pushing forward, keep grinding it out the best I can and just give it 100 per cent tomorrow," he said.
"Overall I feel pretty confident in my abilities to really just keep moving forward and stay patient with myself."
The 27-year-old had three birdies and two bogeys in his first five holes but registered six threes in a row from the ninth to pick up six shots before a double bogey on the 15th halted his momentum.
Day is made of stern stuff, though, and a birdie on the 17th gave him a small cushion.
Spieth birdied the first but looked almost out of contention at the turn as those around him kept picking up shots but a run of three consecutive birdies from the 11th catapulted him back up the leaderboard.
He finished his round with a further trio of picked up shots and will look to emulate Ben Hogan and Tiger Woods on Sunday by winning a third Major of 2015.
Grace recorded eight birdies in a flawless round playing alongside Martin Kaymer, the 2010 champion here who at 11 under is still very much in the hunt after a 65 of his own.
"I think I'm finally getting the hang of America," said Grace, who finished joint fourth at the US Open at Chambers Bay. "This is a dream to play out here. I think I've been playing some great golf.
"The US Open was a good one coming into this and even the Open Championship, just getting the confidence up, knowing that I can do it, can play in this environment and under this pressure.
"I'm as excited as can be. It's another chance, this is what we all play for. We all play to give ourselves the opportunity to get close to a major championship and we're all here for the same reason - we want to win this thing.
"It's just about getting out tomorrow, getting out on the first tee with a smile and hopefully the smile can be there all day."
Rose bogeyed the last to take the gloss off an impressive round containing seven birdies and, for the second consecutive day, a double bogey on the fourth.
"The fourth has cost me a couple of doubles there, so if I can figure that one out tomorrow it will help," the 2013 US Open champion said.
"The only thing that will taste a little sour is that bogey on 18. I hit a good tee shot and was staring down the barrel with a seven iron. I thought it was a good club and misjudged the wind and it came up short, but I was really pleased with the way I hung in there today."
He added: "I can freewheel it a bit tomorrow. Obviously I have the luxury to not have to sleep on the lead and stress about about anything.
"I can have the nothing to lose mentality tomorrow. It is going to be tricky tomorrow if it is windy. That's a harder environment to guard your lead and keep moving forward and it enables the chasing pack to do a better job of catching up."
Tony Finau and Matt Jones are both on 10 under with Dustin Johnson and Anirban Lahiri, who has two European Tour wins this season at the Maybank Malaysian Open and Hero Indian Open, six off the lead.
Brooks Koepka and George Coetzee are both on seven under while Charl Schwartzel is alongside defending champion and World Number One Rory McIlroy a further shot back.
McIlroy is playing his first competitive tournament since the US Open in June due to an ankle injury and, while he has been pleased with his comeback, he admitted after his round he was too far back to challenge on Sunday afternoon.
"It's all about setting a realistic goal and target," he said. "I know that the way the back nine's playing there, the leaders could be 14, 15 under by the time the day ends. So, that would leave me eight shots back.
"In the back of your mind, you still think you have a chance, because that's what your competitive nature tells you. But if you're looking at it realistically, I want to go out there tomorrow and shoot the best score that I've shot this week.
"I've stood still a little on Thursday and Friday, but definitely improved today and you want to improve on that again tomorrow.
"If I do that, I think that, as a whole, the week would be somewhat of a success. It wouldn't be quite what I wanted, but as I said, I can take positives from it and move on."
