Marin Cilic is embracing the pressure of defending his US Open title despite an unconvincing first-round win on Monday.

The Croatian overcame Guido Pella 6-3 7-6 (7-3) 7-6 (7-3) in the first round to continue his streak of never exiting in his opener at Flushing Meadows.

Last year's champion, Cilic said the year's final grand slam suited him most - and defending his crown was of no concern.

"I feel that usually in my career I have been playing pretty well when I was a bit under pressure, even at some Davis Cup ties or grand slam matches where it was going the distance," he said.

"I feel that this tournament could give me also some extra.

"And just feeling that I have won last year over here gives me more belief, you know, that I'm on a special place and that I can play my best tennis over here."

Cilic, who finished with an impressive 44 winners and 27 unforced errors, said returning as the defending champion had been a different feeling.

Awaiting him in the second round is Russian Evgeny Donskoy.

"It changes, absolutely, in your mind looking at the tournament. It's for sure a different approach. But you still have to bring that to your mind, that it's another grand slam, of course," Cilic said.

"It's going to be more important than the other ones, but you still have to simplify it. Still the most important parts of the preparation of the game are going to be the same.

"You know, the performances on the court are the most important. I am feeling that definitely it's a pressure thing to do that, but, of course, if you approach it in the right way, as I'm trying to, it gives me more positive looks at it."