KOHLER, Wisconsin (Reuters) - Jordan Spieth ended one of the best major seasons ever by a player on a bittersweet note at the PGA Championship on Sunday as he had to settle for second place while becoming world number one for the first time.
In pursuit of a rare third grand slam title in the same year, the Masters and U.S. Open champion closed with a four-under-par 68 at Whistling Straits for a 17-under total of 271, finishing three strokes behind the triumphant Jason Day.
Spieth tied for fourth in last month's British Open -- just one stroke short of joining a playoff -- but had the consolation on Sunday of dislodging Rory McIlroy from top spot in the rankings because of his strong finish to the year's final major.
"It's been a very, very good year," Spieth, 22, told reporters after recording his 14th top-10 in 21 starts on the 2014-15 PGA Tour, including four victories and three runner-up spots.
"This is as easy a loss as I've ever had because I felt that I not only couldn't do much about it, as the round went on, I also accomplished one of my life-long goals and in the sport of golf.
"That will never be taken away from me now. I'll always be a number one player in the world. When I look back on this year, the consistency ... and especially being able to step it up in the biggest stages, that's a huge confidence builder."
Spieth, who accrued six birdies and two bogeys on a day of low scoring at Whistling Straits, was already thinking about next year's majors even as he described the mental toll taken while competing for them.
"It was amazing," he said of his form in the grand slam events. "You only get four a year, so to have an opportunity to win all of them is so cool.
"I hope to have a season like this one at the biggest stages again. But it's not easy, it takes a lot out of you. I'm tired right now. I mean, I left it all out there.
"I'm tired from the majors this year because of what it does. It really does wear you out mentally, trying to grind that much."
Editing by Andrew Both