Rafael Nadal has admitted he felt "nervous" during last night's first round US Open encounter with Kazakhstan's Andrey Golubev.

Although the world number two defeated his opponent in straight sets, he had to overturn deficits in each of the three sets, including coming back from two set points at 3-5 in the second.

"For sure I was nervous," said the defending champion afterwards. "That's normal. It's normal to start the tournament like this with some nerves. I was a little bit lucky to win today in straight sets. He was a very difficult player to play.

"And what happened today, he didn't help because he played very fast all the time. All the shots, he was trying to hit a winner on almost every shot. So it was difficult for me to find the rhythm."

He added: "But it's a positive start winning in straight sets. I'm happy I'm through."

Nadal goes on to face France's Nicolas Mahut in the second round later this week.