Federer overcomes plucky Alves challenge

NEW YORK (Reuters) - Four-times defending champion Roger Federer clawed his way into the third round of the U.S. Open with a 6-3 7-5 6-4 victory over stubborn Brazilian qualifier Thiago Alves on Friday.

World number two Federer produced an uncharacteristic 46 unforced errors in the two-hour, 14-minute affair but denied he had a difficult time.

"I was never really in danger, so it was actually pretty good for me," Federer told reporters. "I knew the longer the match would go the more tired he would get."

Federer had 19 aces and lost his serve only once but clearly needs improve his form if he is to become the first man since Bill Tilden in 1924 to win five successive titles here.

"I was struggling to see the ball at the net a little bit with the crowd in the back," said Federer, who played Alves in the cavernous Arthur Ashe Stadium court.

"In the second set when it got tough, he dug out some shots and everything seemed to go against me."

The 137th-ranked Alves was playing his first tour-level event of the year and only the 10th of his career. He said Federer, overtaken recently by Rafael Nadal as the world's top-ranked player after 237 weeks atop the throne, was as good as advertised.

"When Federer slips a little bit, he reaches the finals of the grand slams every time," said the 26-year-old Alves. "He is the biggest player for sure. Nadal is playing good tennis this year but for me, Federer is the best one."

The Swiss will face either Czech Radek Stepanek or Australian Chris Guccione in the third round and remained on track to face third seed Novak Djokovic in the semi-finals of the year's final grand slam tournament.

Federer's play at the net against Alves was spotty and his groundstrokes erratic but the 12-times grand slam champion chuckled when asked if his game was slipping.

"I guess we're talking about it today and if I win the title you forget about it again," he said. "That's usually how it goes."

(Writing by Steve Ginsburg, editing by Pritha Sarkar)