Rafael Nadal returns the ball to Horacio Zeballos during the...

Rafael Nadal returns the ball to Horacio Zeballos during the final of the VTR Open in Vina del Mar, Chile on Feb. 10, 2013. Credit: AP

This hasn't been the best of seasons for Rafael Nadal, the two-time U.S. Open champion.

He has three wins, all in the more minor tournaments of the men's tour. He hasn't come close to a final in the majors, his best showing being quarterfinal losses to Novak Djokovic at the French Open and Tomas Berdych at the Australian. He went out at Wimbledon with a second-round shocker to Dustin Brown. The loss to Berdych at the start of the year was not a bad finish considering where he was coming from.

Last October he had to have his appendix removed the week after a surprise loss to Croatian teenager Borna Coric in the Swiss Open. Coric just happens to be Nadal's first-round opponent at the Open Monday night.

For one of the dominant players of his generation, Nadal has struggled, at least by his standards. After the loss to Djokovic at Roland Garros, his world ranking fell to 10, the lowest it had been since April of 2005. It's No. 8 now, which is his seed at the Open, and he's exudes a quiet confidence in his abilities.

"After a tough year for me, I feel I am closer to the level of tennis I have been in the past," he said Saturday. "That doesn't mean I am going to win. That doesn't matter. Today I feel I am playing well like this. The only thing that remains is results, and I know that. I am passionate with that."

As for the youngster he's facing in the first round: "He's a confident player with a great serve, very good backhand, big competitor. I don't remember so much that match; it was a tough month for me with appendicitis on my mind. I had the surgery the week after. I think I played very bad tennis. Maybe this match will be a different story."

He doesn't tout his chances here, but doesn't discount himself either. "I am not having the best season possible. I am having the worst season in 11 years," he said, but added with a small smile, "I think I can still be some dangerous player in some moments."

Serena stars at night

Not surprisingly, Serena Williams' quest for the calendar year Grand Slam begins with a night match Monday at Arthur Ashe Stadium. There, after the opening ceremonies, she will take on Vitalia Diatchenko in the first match, followed by Rafael Nadal versus Borna Coric. Venus Williams will be second-on Ashe during the day session, playing Monica Puig. Novak Djokovic versus Joao Souza will follow. Defending champion Marin Cilic will play second in Armstrong Stadium, facing Guido Pella.

Sharapova makes return

Maria Sharapova hasn't played since Wimbledon, where she lost in the semifinals to Serena Williams, because of an injury to her right leg that she described Saturday as "a bit of a muscle strain."

She's had to endure several lengthy injury absences during her career. When asked if she would scale back her expectations at the Open because of lack of match play, she responded, "You have to be realistic and have to limit your expectations," she said. "I will try to limit those, but that's never the easy part for a big competitor."

Her opening match Monday will be against Daria Gavrilova, who has a win over her this year at Miami, which Sharapova countered at Rome.

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