Winning the U.S. Open was an out-of-this-world thrill for Marin Cilic, who gives a lot of credit to Croatian tennis pioneer and coach Goran Ivanisevic for guiding him to grand slam glory.

"It's life changing, completely like I was on a different planet so far," Cilic told a small group of reporters after a long night of celebration following his Monday triumph. "It just feels incredible.

"Croatia was crazy time yesterday it was a huge celebration. Also my hometown Zagreb, the whole country was watching," he added, noting he had received some 250 messages on his phone from back home and had not even yet checked Twitter or Facebook.

The towering, 6-foot-6 (1.98 m) Cilic, who routed Japan's Kei Nishikori in straight sets, said he went from promising yet frustrated tennis talent to grand slam winner with the help of his boyhood idol, the irreverent Ivanisevic.

Cilic said Ivanisevic, who rode a blistering serve to the 2001 Wimbledon title, straightened out his own booming service delivery and his doubtful mindset by simplifying things and stressing fun and enjoyment on the court.

The Croat was asked if Ivanisevic had any words of wisdom for him before his first grand slam final.

"'You're gonna be shitting in your pants, I'm telling you that,'" Cilic chuckled in retelling. "'Just try to enjoy it.'"

Unshaven and dressed in a black shirt and blue jeans, the 25-year-old Cilic looked no more scruffy than usual after a night out with family, friends and support team to a Croatian restaurant and a nightclub until 5 a.m. ET .

After a spate of early morning TV appearances, Cilic perked up when asked about his history with Ivanisevic.

"The first time we met I was ball boy for him and Thomas Muster at one event close to my hometown when I was eight or nine," said the Bosnian-born Cilic.

"And then after when I was 14 in Zagreb in 2002 he was there recovering from his shoulder injury, shoulder surgery, so he played with me several times.

"It was huge moment for me to be with him, play with him and get some advice. He just pointed me in the right direction and helped me out a lot."

An obviously talented player, Cilic reached the semi-finals of the 2010 Australian Open but was not able to repeat that success and grew frustrated and tinkered with his technique.

It was time for a coaching change, and last September Cilic found a perfect match in teaming up with Ivanisevic.

"When I worked with Goran, he has perfect serve and he was doing it so simple. It took us about 10 minutes to put it in the spot," he said.

Cilic remembers watching Ivanisevic's Wimbledon win on TV as a 12 year old.

"He was a hero for all Croatia at that time, especially because he had lost three times (at Wimbledon) and reached again the final," he said.

Cilic said breaking through at Flushing Meadows could provide him with some critical confidence.

"It will be easier for my mindset," he explained. "You know that if you are playing your game well you can beat anybody.

"That's what the best guys know, that when they play their own 'A' game they don't have to think about anything. That's for me the huge gain."

Cilic longs to add more titles to his resume, but does not deny that emulating Ivanisevic again would be satisfying.

"Every grand slam is worth the same, but Wimbledon is very special for all the Croatians and probably for most of the guys that are playing.

"It's just something in the air."

(Editing by Frank Pingue)