Rafael Nadal's first match as a defending U.S. Open champion wasn't pretty but it was enough for a win.

Now, only time will till if his struggles were a case of opening-night jitters or something more serious.

The second-seeded Nadal found himself in a tougher-than-expected tussle Tuesday night, needing 11 minutes short of three hours to finish off 98th-ranked Andrey Golubev of Kazakhstan, 6-3, 7-6 (1), 7-5.

"It's normal to start the tournament like this with some nerves," Nadal said. "And what happened today, he didn't help because he played very fast all the time."

While the women's draw is as open as ever, many believe Nadal has only two main challengers. There's top-seeded Novak Djokovic, who is 5-0 against Nadal this year and was leading 6-0, 5-1 over Conor Niland on Tuesday when Niland retired with food poisoning. And there's third-seeded Roger Federer, a five-time champion here, who won his first match easily Monday.

Nadal hardly breezed through his. He said he was happy to get through such a tough test, that no player wants to be in top form at the beginning. Still, the stats were hard to ignore.

He had to fight off seven set points in the second and needed to rally from two breaks down in the third.

He lost his serve six times. This for a player who lost serve a total of five times in his run to the championship in 2010. But Nadal said it's his groundstrokes, not his serve, that will determine his fate over the next two weeks.

"The people forget a lot of things, but last year my first match was really bad," he said of his 7-6 (4), 7-6 (4), 6-3 win over Teymuraz Gabashvili. "That's the truth, even if I didn't lose my serve. I played bad against a similar opponent as today. He played very fast."

Indeed, Golubev went for everything and forced the action with Nadal. Golubev finished with 41 winners and 59 unforced errors compared to 18 and 16 for Nadal.

He moved Nadal around, kept him hitting from well behind the baseline and had more than his share of chances to capture momentum, a set, maybe even the match.

"If you don't think about the points, it was not bad performance," he said. "I mean, you have to win the points when you have to win. For example, like second set or third set when you serve for the set."

But he didn't, and Nadal moved on for a second-round match against Frenchman Nicolas Mahut — he of the famous 70-68 fifth set against John Isner at Wimbledon last year.

Isner, 21st-seeded Andy Roddick, fourth-seeded Andy Murray and 2009 champion Juan Martin del Potro are among those who play first-round matches Wednesday, while Venus Williams and third-seeded Maria Sharapova will play their second rounds in Arthur Ashe Stadium.

Other winners on the women's side Tuesday included No. 4 Victoria Azarenka, No. 10 Andrea Petkovic, No. 11 Jelena Jankovic and three young Americans: Sloane Stephens, Coco Vandeweghe and Vania King.

Two seeded men lost: No. 16 Mikhail Youzhny was beaten by Ernests Gulbis of Latvia 6-2, 6-4, 6-4, and No. 32 Ivan Dodig was eliminated 6-7 (6), 6-3, 6-0, 2-6, 6-2 by Nikolay Davydenko of Russia, who was a U.S. Open semifinalist in 2006 and 2007 and has slid from third in the rankings to 39th.

No. 5 David Ferrer and Americans James Blake and Donald Young were among the men who advanced.

As did Nadal — though nothing seemed easy on this day. He is regaining confidence after a summer in which he didn't play much and lost early in his two U.S. Open tuneups.

"You have to find your confidence," he said. "The confidence is spending hours on court, competing better, winning matches. Today was one of the matches."

Based on reporting by the Associated Press.

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino