The title, of course. And the shiny silver trophy. And the $3 million top prize, too. Plus the newfound celebrity status that put him in front of millions of TV viewers as he made the rounds to read a Top 10 list for David Letterman and chat with Charlie Rose and appear on "Live Kelly and Michael."
"It's life-changing, completely," Cilic said. "Like I was on a different planet."
The indelible memory that Cilic expects to last the longest from the whirlwind came right after the final point of his 6-3, 6-3, 6-3 victory over Kei Nishikori in the final at Flushing Meadows on Sunday evening: climbing into the stands to embrace his coach, Goran Ivanisevic, and the rest of his support group.
"I was so happy to go out there to my team and to hug them and to celebrate with them," Cilic said, a smile creasing his unshaven-for-superstition face. "It was the best moment of the day."
The first man from Croatia to win a major singles title since Ivanisevic at Wimbledon in 2001, Cilic credits his mentor with providing significant help since they began working together a year ago, during the player's four-month doping suspension.
They had first met when Cilic was not yet 10 years old and served as a ball boy during a match played by Ivanisevic in Zagreb. Later, when Cilic was a pro, they chatted regularly.
But starting last September, the real work began. Ivanisevic tweaked the 6-foot-6 Cilic's already imposing serve, for example. More important, both men say, was the sense of self-belief Ivanisevic instilled in Cilic and the realization that it's necessary to try to have fun while playing.
"I just told him, 'Play. Go play. Go show the world what you can do,'" Ivanisevic said. "I'm not a guy who's like a general. I was a player, so I know when to back up, when to push him. ... He needed a little kick. I made this kick. Look at him now. He's on the top."
Cilic, who turns 26 later this month, said that he found himself no longer having fun with his sport before the guy he calls "a hero" came along.
And Ivanisevic's largest contribution to the win in Cilic's first Grand Slam final came not the day before he faced Nishikori, when they talked tactics.
It came, rather, during a pep talk in the locker-room right before Cilic walked out for the match.
"We sat a couple minutes. He said, 'Go out there. Enjoy. You deserve it. Have fun a lot,'" Cilic recounted.
He said Ivanisevic then told him the on-court nerves would be overwhelming, but to try to relish it all anyway.
Cilic managed to do just that, part of a remarkable title run that included taking the last 10 sets he played, including all three against Roger Federer in the semifinals.
And going forward?
Cilic, only once before a Grand Slam semifinalist, thinks the past two weeks will pay dividends for years.
"It will be easier for my mindset," he said. "I don't know if it's going to be easier to win it again. I hope it will be, for sure, and that it will happen again."
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