HAVEN, Wis.Hes the best in the world now, at least in the rankings.No, Jordan Spieth didnt win the PGA Championship, but he finished second. This after wins in the Masters and U.S. Open and after missing the playoff in the British Open by a single shot.It was a record-breaking year in which he finished with the lowest cumulative score for all four majors in a single season at 54 under par.But beyond the trophies and the records, Spieth has achieved in 2015 what every athlete in every sport hopes to gainconsistency.The standard for consistency is Jack Nicklaus. Yes, Tiger Woods had some wonderful years in taking home 14 wins in the big ones. But Nicklaus not only had 18 victories in the majors, he had 19 seconds. He was always there, always at the door whether it opened for him or not.In the entire decade of the 1970s, Nicklaus was outside the top 10 in majors only five times. That is the ultimate example of being consistentAnd in this magical year of 2015, nobody has been as consistent as Spieth. In addition to his incredible performances at the majors, he also has two other wins on Tour. And three second-place finishes.And a third. And a fourth.That's nine tournaments in which he was no worse than fourth place. And now at age 22, hes in a special place, above Rory McIlroy and everyone else, atop the golfing world.Its been a very good year, said Spieth in what surely must be labeled an understatement.He was speaking a few minutes after he and playing partner Jason Day stepped off the 18thgreen at Whistling Straits, after Day stepped into his first major, winning the PGA with the lowest cumulative score ever in one of the sports big four, 20 under par.Day's five-under 67Sunday helpedhim finish three shots ahead of Spieth. Three shots here and one in the British at St. Andrews and Spieth could have taken the Grand Slam and won all four majors in a calendar year, which no one has done.But he wasnt thinking of possibilitiesrather, of achievement.Its amazing to think about it, he said, reflecting about the British and PGA. You can look at it two different ways, four shots shy of the Grand Slam or look at it from a negative view. Where maybe one putt and I would have one major this year. If Dustins goes in [Dustin Johnsons birdie putt on 18 at the U.S. Open], I should be fortunate we caught a break there. Then we had a chance to win another."While Sunday was Days day, to get cute, it was Spieths season, a season that kept the sports world attentive and fascinated.That consistency has also yielded another impressive benefit.[Being No. 1 in the world] is one of my life-long goals, said Spieth. That will never be taken away from me now. Ill always be a No. 1 player. Thats what Ill look back on, the consistency. We dont play to take a week and just sneak by the cut and tie for 35th. ... It was fun waking up today, knowing Ive got another chance to win a major.And there's certainly no sense that he won't be able to keep the momentum going.As is Rory McIlroy, whom he overtook in the world golf rankings, Spieth is outspoken, a conversationalist who loves to talk golf as much as he loves to play it. And he certainly loves to play it.It was amazing. You only get four a year. 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.The season lifted him into fame. He has to ask for a corner booth in restaurants. But the season also wore him down.Its not easy, said Spieth of staying in contention over a stretch of some five months, from the Masters in April through the PGA in August. Im tired right now. It really does wear you out mentally, trying to grind that much.Theres a reason I have a receding hairline. That kind of pressure building and that kind of stress. And as much as much as a thrill as it is, it can wear you down.It also can build you up. The depth of talent on the PGA Tour is greater than any time in history. To know hes triumphed against players who are both strong and fearless must give Spieth not only satisfaction but unlimited confidence.And with Spieth's emergence in 2015, Day's breakthrough win on Sunday and McIlroy's undoubtedly burning desire to get back to No. 1, the sport is set up for an exciting future, with the laid-back Texan leading the charge.What I imagine all our dreams were as kids was to win majors. Major championships are what were remembered for in this sport.Major championships and consistency. Jordan Spieth has both.ArtSpanderis a winner of the 2009 Lifetime Achievement Award in Journalism from thePGAof America. Unless otherwise noted, all quotes were obtained firsthand. Click here to read full news..