By Julian Linden
NEW YORK (Reuters) - Rafa Nadal is hoping for a better performance in his second round match at the U.S. Open Friday to restore his confidence and his wobbly serve.
The defending champion won his opening match in straight sets but there was one damning statistic that does not augur well for his hopes of winning back-to-back championships.
His unseeded opponent, Andrey Golubev of Kazakhstan, broke Nadal's serve six times in the match. That was one more than the total number of times Nadal was broken in seven matches at the tournament last year.
"(It) is impossible to win this year," Nadal said, before reassuring his audience. "No, I am joking.
"But I can improve my serve and that is what I am doing."
Nadal has been struggling with his confidence after losing the Wimbledon final and number one ranking to Novak Djokovic but said he was slowly regaining his self-belief and expects an improvement against Frenchman Nicolas Mahut.
"You have to find your confidence. You get it from spending hours on court, competing better, winning matches," Nadal said.
"I am very happy to be through, and I am happy to be playing better."
Britain's Andy Murray is also looking for an improved performance after he too won his opening match in straight sets. He plays his second match of the tournament, against Robin Haase of the Netherlands.
Murray was below his best in his first match but admitted he was feeling some nerves after once again lumbered with the expectation of ending his country's long grand slam drought.
"Try being a British player going into a grand slam. It's not easy," he said.
Former world number one Maria Sharapova leads a heavy presence of Russian women on the fifth day of the championship.
She faces Flavia Pennetta in the third round, the first time the seeds start lining up against each other, while her compatriots Vera Zvonareva, Maria Kirilenko and Nadia Petrova are also in action.
The U.S. will be assured of at least two men in the third round with two all-American clashes scheduled for Friday. Former champion Andy Roddick tackles Jack Sock in the Arthur Ashe Stadium while the big-serving John Isner takes on Robby Ginepri.
(Editing by Ian Ransom)