By Larry Fine

SPRINGFIELD, New Jersey (Reuters) - The golf year started with buzz about the dominance of a new Big Three of Jason Day, Jordan Spieth and Rory McIlroy that echoed the storied days of Jack Nicklaus, Arnold Palmer and Gary Player.

The major championship season ended, however, with four maiden major winners, as American Jimmy Walker capped a grand slam sweep for first-timers at the PGA Championship where the Texan toughed it out over a 36-hole final day to triumph.

The results in the majors suggest that parity has returned in the post-Tiger Woods era.

The victory by Walker, 37, followed Englishman Danny Willett at the Masters, American Dustin Johnson at the U.S. Open and Sweden's Henrik Stenson at the British Open, striking four hefty blows for those on the 'yet to win a major' list.

"I think it shows that everybody out here playing is really good, and everybody's got a chance to win," Walker said after a bogey-free final round at rain-battered Baltusrol capped by a last three-foot par putt that kept world number one Day at bay.

Day, who won the PGA last year at Whistling Straits for his long-awaited major victory, showed off his wondrous talents and competitive grit by turning up the heat on Walker by firing a two-iron to the green on the par-five last hole and draining the putt for eagle that forced Walker to par for the win.

The 28-year-old Australian said he pleased by the way he played in defense of his PGA title and said expectations might have been driven too high by the exploits of Woods in his heyday.

Woods dominated for more than a decade, winning 14 majors between 1997 and 2008, while nobody else among active players has more than the five majors collected by Phil Mickelson.

"I think the bar's been raised ever since Tiger Woods kind of came around. I think everyone expects if you're in the lead or if you're a favorite to win, they expect you to win, and if you don't, then you're in a slump," said Day. "It's very, very difficult to win golf tournaments.

"Golf is a very difficult game, on top of trying to manage the mental part of the game, as well."

Day had the best 2016 majors season of the so-called Big Three, finishing second by one shot at the PGA, threatening at the U.S. Open in the final round before tying for eighth and finishing tied for 10th at Augusta.

Spieth, who won the Masters and U.S. Open in 2015, seemed a lock to repeat at Augusta National as he carried a five-shot lead into the back nine on Sunday.

A quadruple-bogey seven at the short par-three 12th, where he put two balls into Rae's Creek, left him trailing be three on his way to a tie for second.

McIlroy's best major was a tie for fifth at the British Open, but he never threatened finishing 16 shots off the pace.

"I think the winners that you've got this year just go to show you it's been so varied," said Willett, 28, who had won four times on the European Tour before his Augusta victory.

"Obviously Henrik being 40 and finally capturing a major, surprising it's his first because of how good of a player he is.

"And obviously Dustin has come so close over the last five or six years, to finally polish one off.

"I think it just goes to show the strength and depth throughout golf at the moment."

Four-times major winner McIlroy concurred. "There's no doubt that the fields are very deep. You know, any number of guys can turn up on a major championship week and win," the Northern Irishman told reporters at Baltusrol.

Spain's Sergio Garcia, long on the list of 'best players yet to win a major', blamed the media for all the hoopla over the

Big Three.

"I think that it is something that you guys have always done," he said in an interview session. "You've always kind of gone with the Big Three or the Big Four or the Big Five or whatever.

"At the end of the day, on my behalf, the only thing I can do is keep improving, keep getting better, keep doing what I know how to do and then the rest doesn't really affect that much.

"It's nice to see new major winners. But every week is a new world. Every week is a different story."

(Editing by Andrew Both)