Jordan Spieth has turned his most humbling defeat into the basis for what Rory McIlroy calls his "greatest weapon" as golf's top young stars collide at the 99th PGA Championship.
World number two Spieth, a 24-year-old American who won last month's British Open, and fourth-ranked McIlroy, a 28-year-old from Northern Ireland seeking his fifth major title, are the favorites when the year's final major tournament tees off Thursday at rain-dampened Quail Hollow.
Spieth, also the 2015 Masters and US Open champion, could become only the sixth man to sweep the four major titles in a career after Jack Nicklaus, Tiger Woods, Ben Hogan, Gary Player and Gene Sarazen. And he would be the youngest to achieve the feat.
"He has got that knack. I call it resilience," McIlroy said of Spieth. "He gets himself in positions in tournaments where you don't think he can come back from, and he does. It's awfully impressive. It's a mental thing.
"Resilience, mentally tough, strong -- whatever you want to call it, that's his biggest asset. Being able to forget about a bad shot and move on to the next one, that's his greatest weapon."
Spieth said that ability was earned the hard way after his back-nine meltdown in last year's Masters. He enjoyed a five-stroke lead entering the back nine but stumbled out of the lead with a quadruple bogey at the par-3 12th and shared second to England's Danny Willett.
In some ways, the humbling defeat was liberating for Spieth.
"When we get into these high-pressure situations, when I get off-course a little bit, there's no negativity that comes into play in my mind and maybe that makes a difference," he said. "It's not like the fear of it not going well. I've already had enough not go well that I've almost accepted, OK, if this doesn't work out, then it doesn't work out, I'm going to have more chances.
"Just that kind of freedom allows me to take the fear away of any potential bad situation. I mean, I've gone through what will probably and hopefully be the worst loss of my career in the most public eye that golf has. So everything else that could happen is much lesser and therefore, has probably helped me since then to focus and only see the positive that could come out of a situation."
McIlroy, who hasn't won a major since the 2014 PGA and hasn't won any title since last year's Tour Championship, could join Woods and Nicklaus as the only players to take five majors before turning 30 by winning this week on a course where he has won twice in PGA Tour events and lost another in a playoff.
Add that to McIlroy's love of PGA set-ups, having won the event in 2012 and 2014, and success in wet conditions, notably his 2011 US Open triumph, and he figures to rival Spieth for the Wanamaker Trophy.
"Rory is a guy who is very difficult if you come into a one-on-one type situation, especially in majors, because he's not afraid to hit the shot," Spieth said. "He plays so aggressively and that's what you have to do to win.
"If you're matched up on Sunday, and you get to choose somebody, you obviously want to be able to play against somebody like Rory who is one of the top couple most accomplished players in this field. But he's one to fear in that position because of what he's capable of doing and how he's going to do it.
"It's cool that we've both had the success we've had at such a young age and I think the coolest part about it is the question of what's it going to be like for the next 20, 25 years.
"And that's kind of what is the exciting part when we think about it, too. We're friendly with each other and really want each other to do well because it does push each other."
And they aren't alone. Other rising young talents such as Japan's Hideki Matsuyama, who won last week at Akron with a closing 61, and Spain's Jon Rahm are seeking their own first major wins this week.
"It's not two of us. It's really eight to 10 right now," Spieth said. "Look at what Jon Rahm has done in really his first full year out here. Really incredible, a guy who is going to win major championships.
"The way Hideki is playing, and he's obviously coming in here as probably the hottest player in the game at 25... a lot of young guys out here are all pushing each other to get better."