Rory McIlroy has already won four majors before his 26th birthday, and appears to be the heir apparent to Tiger Woods and the next to try to break Jack Nicklaus’ record of 18 majors. Every great golfer needs an equally great and hungry player alongside him if he wants to get the most out of his career.

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Jack Nicklaus had Arnold Palmer, then Tom Watson. Woods had Phil Mickelson. Now, McIlroy has Spieth. The duo are No. 1 and No. 2, respectively, in the world rankings.

Though McIlroy has been dubbed the next Tiger, it was Spieth who put up Tiger-like numbers in just his second Masters.

The era of Woods and Mickelson is closing, and the embers have sparked a potentially sport-changing rivalry, one that golf needs to survive once the inevitable occurs and Woods can no longer play.

One thing the Woods-Mickelson rivalry lacked was consistent pressure by Mickelson. It wasn’t until 2004 that Lefty finally won his first major. By that time, Woods had already completed the “Tiger Slam,” becoming the youngest person to win the career grand slam.

The two did have some memorable stare-downs, including at Doral in 2005 where Woods eked out a one-stoke win over Mickelson. Mickelson then had a nice stretch to end ‘05, beating Woods by two at the PGA Championship, then topping him again in the 2006 Masters. Despite those close calls, Mickelson never consistently challenged Woods the way golf fans craved. It was Vijay Singh, not Mickelson, who finally knocked Woods off his perch as the No. 1 golfer in 2004, ending Woods’ streak of 264 weeks at the top.

Woods lacked a player who drove him and truly equaled him during his dominant stretch. His closest competitors in his major wins were twinkle-toed Sergio Garcia and journeyman Bob May. Players like Rich Beem and Ben Curtis won majors when it should have been Mickelson adding to his total.

Spieth now sits three majors behind McIlroy, but is also four years younger. He possesses the poise and calmness of a golfer in his mid-30s and hasn’t let success change him to this point.

Thoughts like his day-after tweet have quickly made Spieth a fan favorite from all age groups. He decided to keep his commitment to play in the RBC Heritage, the event that follows the Masters, despite playing in the last three tournaments and having an obvious reason to back out. Small things like that exemplify Spieth’s determination to not only become a great golfer, but a great person as well. Before the Masters, Spieth echoed said he looked up to Palmer over Woods and Nicklaus, because Palmer was a champion on and off the course.

While Spieth is now the front-runner, he’s not the only young star who could be an able rival to McIlroy. Jason Day, 27, has runner-up finishes in the Masters and U.S. Open, as well as a third at Augusta. He has battled wrist injuries, but is supremely talented and currently sits fifth in the world.

Rickie Fowler, 26, looked like he was going to raise the mantle as America’s next great golfer when he went to-to-toe with McIlroy in two majors a year ago, while finishing in the top five in all four majors.

Japanese wunderkind Hideki Matsuyama, 23, won the Memorial last year and owns a top 10 finish in three of the four major championships. Matsuyama boasts unprecedented rhythm with his swing, and he displays the same maturity as Spieth in handling the Japanese media.

That group doesn’t even include Patrick Reed, 24, who has won four tournaments on tour in the past year and a half, or Brooks Keopka, 24, who broke through with wins on the European and PGA tours in the past eight months.

There is so much young golf talent chasing McIlroy and Spieth that this generation could be a highlight in golf lore. The two have now won the last three majors between them, and will be favorites in June when the U.S. Open heads to Chambers Bay.

Buckle in, ladies and gentlemen — the next 20 years should be one wild ride.