Rafael Nadal doesn't yet consider himself among the best tennis players in history.

Rafael Nadal of Spain celebrates with his championship trophy during the awarding ceremony for the men's singles event at the US Open tennis tournament in New York Sept. 13, 2010. Rafael Nadal won the champion of the event after beating Novak Djokovic of Serbia in the final 3-1 on Sept. 13. [Xinhua/Shen Hong]

No matter that he is only the seventh man to win each Grand Slam title, or that only six men finished with higher totals of major championships.

A day after achieving his first US Open championship, here is as far as he was willing to go on Tuesday in an interview with The Associated Press: "I know I am a little bit in the history of tennis now, winning this last tournament. But I'm still 24, so we will see where I am when I finish my career."

Indeed, Nadal insisted he can't be sure he will add to the Grand Slam singles trophies he already has earned - five at the French Open, two at Wimbledon, and one each at the Australian Open and US Open - let alone challenge Roger Federer's record of 16.

"I don't know if I'm going to win another one," Nadal said, earnest as can be.

He paused, then explained: "You never know when this will start, and when this will stop."

After playing in Federer's shadow for years, Nadal is now the one to watch.

As ATP chief executive Adam Helfant put it during the US Open: "Rafa is a rock star when he comes out to play here."

It's Nadal who is ranked No 1.

It's Nadal who has established his bona fides on all of tennis' surfaces.

It's Nadal who has a chance to finish off a Rafa Slam by winning the Australian Open in January. He would be the first man with four major titles in a row since Rod Laver pulled off a true Grand Slam by claiming all four in 1969.

A little more than 12 hours after finishing his four-set victory over Novak Djokovic in the US Open final for a third consecutive major title, Nadal was still coming to grips with the significance of the result.

"It's difficult to stop and think," Nadal said. "Maybe on the plane and after, when I get home, it will be easier."

He threw his head back and laughed when asked whether he is the type to think back to this year's Australian Open - he retired from his quarterfinal with a knee injury, the lone blemish on his 25-1 Grand Slam record in 2010 - or forward to next year's.

"No. I am very happy now (with) what I did. I know how difficult it is to win every tournament," he said. "For sure, I'm going to try my best to be ready for Australia. But my first goal is to try to finish this season playing better than ... other years at the end of the season."

Give Nadal credit for consistency. He's always talking about how important it is to him that he keeps improving.

Asked which of his many accomplishments makes him proudest, Nadal began by mentioning his first French Open title, in 2005; then his second, the next year; his first Wimbledon championship, earned with a victory over Federer in 2008's "dramatic final," as Nadal called it; his gold medal from the 2008 Beijing Olympics; his 2009 Australian Open title; Spain's 2004 Davis Cup title.

Then, right when it seemed Nadal might very well keep going until he'd named every single thing he's won, he turned more contemplative.

Referring to the "very difficult" second half of 2009 - which included knee and abdominal injuries, the only French Open loss of his career, his withdrawal from Wimbledon, and his parents' separation - Nadal spoke about rebounding so strongly.

"I wanted a lot to be back," he said. "And now, I am better. I did better than before. That's very huge."

And yet, as well as Nadal has played since April - 43-3 with six titles - and for two weeks at Flushing Meadows - coming within a second-set lapse against Djokovic of becoming the first man in a half-century to win the tournament without dropping a set - he is hardly satisfied.

One example: He thinks he played only "so-so" at the start of the Open.

What still needs work, then?

Nadal sighed, then rattled off a serious "To Do" list:

make sure his serve gets even better, even though he won 106 of 111 service games en route to the title, tying the tournament record for fewest lost;

fine-tune his court positioning;

improve his slice backhand and volleys;

and, he said, his backhand and forehand winners "can improve a little bit more."

"That's what's so frustrating, a little bit: He's getting better each time you play him," said Djokovic, the 2008 Australian Open champion and twice a runner-up in New York.

After jetting home to Spain on Tuesday, Nadal plans to take a break for two days, then return to the practice court on Friday.

It barely gives the guy any time to think about his place in history.