Jordan Spieth's hopes to become the youngest player to complete a career Grand Slam by winning the 99th PGA Championship vanished with a closing double bogey in Saturday's third round.

The 24-year-old American, who captured his third major title at last month's British Open, fired a par-71 Saturday to stand well off the lead in an event he says will be his most difficult major to capture.

"The PGA Championship, I think, is going to be the toughest for me," Spieth said after firing a par-71 Saturday. "If we look historically back on my career, I think I will play this tournament worse than the other three majors just in the way that it's set up."

World number two Spieth, who won the 2015 Masters and US Open, has two missed cuts, a 2015 runner-up effort and a share of 13th last year in his four prior PGA starts.

"I feel like my game truly suits the other three majors maybe more than a PGA," Spieth said. "But I believe we can play anywhere and can win anywhere. It's just a matter of having everything in sync at the right time."

That was not the case this week at Quail Hollow, where Spieth struggled with his putter until back-to-back birdies to close Saturday's front nine and three birdies in a row starting at the 14th.

"Any week you don't have a chance to win, you've fallen short of where you would like to be," Spieth said. "Disappointing would have been going home after two days."

But Spieth says there are things to be gained from every round, citing a strong final round at the US Open with building momentum for his British Open victory at Royal Birkdale.

"It was US Open Sunday, I was out of it, but I gathered a little something off that Sunday round that led to two wins and two tournaments after that including a major," Spieth said. "Just one round like that can do that. That's what I'm looking to do here."

And while he won't be the youngest, Spieth expects to have many more chances to join Jack Nicklaus, Tiger Woods, Gene Sarazen, Ben Hogan and Gary Player in completing the career Grand Slam.

"I didn't have it written in a diary from when I was young that I need to win a career grand slam as the youngest ever. That wasn't the goal," Spieth said.

"The goal was to try and win them all. The goal was to try and get on the PGA Tour and then from there see what happens. And yeah, I have a lot of opportunities."

Spieth said he did discover something that improved his putting, even if it wasn't enough to lift him into contention.

"I was trying to play aggressive to see how many birdies we could make," Spieth said. "Found a little something that I was trying out there. I felt very good about the way I was stroking it and the way I played the last 10 of the last 11 holes."

He wouldn't get into specifics, but added, "Where I have been searching a little bit, I found what I think was the solution. It led to a lot better strokes, therefore I can focu