Jordan Spieth took a big step in Australia for his confidence and career. It was a mere baby step, however, toward being a legitimate rival to Rory McIlroy.

Then again, he's in good company.

Golf thrives on good rivalries, even if they are one-sided, and most of them are. That could be the case with McIlroy, who at 25 already has won four majors. Tiger Woods, Jack Nicklaus and Bobby Jones were the only other players to have that many majors at such a young age. Boy Wonder also has 14 wins around the world.

Even with that landslide win in the Australian Open, and with one of the great closing rounds of the year, Spieth still only has two victories.

That's as many as Rickie Fowler.

And Jason Day.

Patrick Reed has three victories. He can rightfully claim to be among the top five in the world, but only if he's talking about five players in the same age group as McIlroy with the potential to challenge him over the next decade.

Rivalries aren't restricted to age, of course. Nicklaus was 10 years younger than Arnold Palmer (and wound up winning 11 more majors). Tom Watson was nine years younger than Nicklaus. The next four players behind McIlroy in the world ranking — Henrik Stenson, Adam Scott, Bubba Watson, Sergio Garcia — are all about a decade older.

Woods is in a league of his own. There remains potential for a rivalry, though Woods is an old 39 because of mounting injuries. Woods is very much like Nicklaus, who had a revolving door of rivalries throughout his career — Ernie Els, David Duval, Phil Mickelson, Vijay Singh. There's still time to add McIlroy to that list.

As golf winds down another season, one question for next year is which player in his 20s might emerge as a rival to McIlroy.

"There's a bunch of young guys that could break through and become legends of this game — Rickie Fowler being one of them," McIlroy said after a few months ago after adding his second straight major. "You just have to look at how he's played the majors this year."

Fowler joined Woods and Nicklaus as the only players to finish in the top five at all four majors, except that he didn't win one.

"Jordan Spieth is another," McIlroy said. "There's a lot of great, young players that will be playing in majors for the next sort of 20, 25 years that can really make their mark on the game."

Spieth deserved mention because he was 21 and in his second year. He had only one victory at the time (John Deere Classic), but he went down to the wire at the Masters and The Players Championship this year, after having the best rookie campaign of anyone since Woods.

But it starts with winning.

Nicklaus and Palmer never went head-to-head as often as the greatness of their rivalry suggested. Nicklaus and Watson clashed in three majors over a five-year stretch. Greg Norman and Nick Faldo took turns at No. 1, with Norman spending more time at the top and Faldo winning the showdowns in majors.

For all the rivals Woods had, Mickelson stands out with the second-best record in PGA Tour victories (42) and majors (five)

There is not a single definition of a rivalry. You just know it when you see it.

Spieth was asked a few months ago what it would take for him (or Fowler) to become a true rival. He mentioned winning majors, before pausing to state the obvious.

"We need to win another TOURNAMENT first," he said.

So consider the Australian Open a baby step. Spieth moved up to No. 11 in the world, which felt a lot more than 10 spots in the ranking from McIlroy.

"I believe that I'm still far away because I believe that I have to win at least a major or two in order to at least start to significantly progress to that goal," Spieth said.

McIlroy was runner-up in both of Fowler's victories, in South Korea and at Quail Hollow. Fowler, however, hasn't won in two years, which led him to say after the PGA Championship that McIlroy was "definitely a step ahead of me — or two. Or four majors."

Most intriguing about Fowler is that he and McIlroy have been competing against each other since the 2007 Walker Cup. McIlroy turned pro the next year, Fowler in 2009. For now, that's where the similarities end.

"I definitely have some work to do, but there is a potential of him and I being able to play against each other for a long time to come, both being the same age," Fowler said. "There's a lot of guys under 30 in the top 50 in the world right now. So as far as Rory and I sticking out, I think Rory is kind of out on his own right now. And we'll see if a few of us can rack up some more wins."