Nicklaus and McIlroy struck up a friendship over the last couple years when the Northern Irishman went to see The Golden Bear for tips on the game, notably, how to win at the majors.
The Bear, who knows a little something about good golf swings, said the 22-year-old has the kind of swing that can hold up over time. It certainly held up Sunday, over a closing round 2-under 69 that helped McIlroy break the U.S. Open scoring record that Nicklaus shared with Woods and two others.
"His rhythm is so beautiful, his tempo, it just stays the same all the time," Nicklaus said in an interview on NBC. "He doesn't try to kill it, doesn't try to do anything unusual with the golf ball. He hits it a little harder at times when he wants to put a little power in it and I think that's fine."
Nicklaus was 22 when he won the first of his 18 majors in 1962 — three months older than McIlroy is now.
Their most recent discussion came last month, while McIlroy was still reeling from his collapse at the Masters, where he took a four-shot lead into the final round but shot 80 and finished 15th. Nicklaus said he didn't really give McIlroy advice, but instead asked if he'd learned anything from his mistakes.
"He said, 'Yeah, I think I did,'" Nicklaus said. "I said, 'Well, make sure you did, because the next time you get yourself in that position, you've got to remember what you did and what you didn't do and remember what you want to do and go do it.' "
As the week at Congressional progressed, McIlroy never shied away from talking about his mistakes at Augusta. In fact, he embraced the experience, used it as a learning experience. After getting a big lead going into the weekend, he didn't look back.
"You sit down with the most successful player that's ever lived and for him to say that he expects big things from you, that you should embrace the pressure, those are great things to hear from someone like him," McIlroy said. "To be able to come out this week, and after what he said to me, and put a little bit of that into practice so early is a nice feeling."
Even before he had closed out his win, McIlroy was answering questions about becoming a multiple major winner. Padraig Harrington was predicting he might someday eclipse Nicklaus' record.
McIlroy is the youngest U.S. Open champion since Bobby Jones in 1923, and Nicklaus says there's some pressure taken off by winning the first one at such a young age.
"I hope he understands he is a golfer first," Nicklaus said. "He will be and already is a celebrity, but he is a golfer first. Right now he is a very good golfer, but if he wants to be a great golfer, he needs to learn how to deal with it and learn how to handle all the things on the side."