Cilic, who has a 19-13 record this year as he has battled a shoulder injury since winning his maiden grand slam at Flushing Meadows, blasted home 19 aces to sweep past Russian Evgeny Donskoy 6-2 6-3 7-5 on Wednesday.
The Croatian said returning to the blue court at Arthur Ashe was a moving experience, and after a first-round victory at Louis Armstrong Stadium he was back at his favourite place.
“This court is very special for me, brings back special memories,” said Cilic. “It’s sort of unreal. I was working all my life to win a grand slam and now I’m in position to defend one.”
Cilic said flashing back to his 2014 triumph was inspiring.
“I feel that these things are close to me, somewhere around in the air, and I’m feeling that I’m close to finding them again and playing really good tennis,” added the ninth-seeded Cilic.
“When it counted I was making a lot of first serves and really playing the attacking tennis that I was also playing last year.
“Conditions out there on Arthur Ashe Stadium are a bit quicker, the court is quicker, and that suits my game.”
The 26-year-old Croat lost serve only once to the 139th-ranked Russian and took less than two hours to advance.
“I was very relaxed to come on the court,” he said. “So glad to be back on the Arthur Ashe with good tennis.”
Cilic missed the Australian Open due to his shoulder injury, reached the fourth round of the French Open and the quarters at Wimbledon before falling to world number one Novak Djokovic.
Now the big-serving Croat is feeling stronger and feeling good vibes from the U.S. Open centre court.
“I had pretty good Wimbledon, but over there I still felt that with my tennis it was a little bit up and down,” Cilic said.
“But now I’m feeling that the way I’m hitting the ball, the way I’m moving on the court, the way I’m serving, it’s really satisfying.”
Cilic will next play either Bulgarian 17th seed Grigor Dimitrov or Kazakhstan’s Mikhail Kukushkin, but the Croat is ready for anything at his favourite place in tennis.
(Editing by Frank Pingue)