NEW YORK (AP) — Rafael Nadal’s first match as defending U.S. Open champion was hardly a tour de force.

He would fall behind in a set, then come back. Fall behind, then come back.

His serve was broken six times; that happened a total of five times in seven matches during his 2010 run to the title at Flushing Meadows. His shots didn’t have their normal depth. He needed to save seven set points during the second set.

Locked in a struggle for nearly three hours, the second-seeded Nadal eventually got past 98thranked Andrey Golubev of Kazakhstan 6-3, 7-6 (1), 7-5 on Tuesday night to reach the second round of the U.S. Open. “Well,” Nadal conceded, “I was a little bit lucky to win today in straight sets.”

That’s for sure.

Three-time U.S. Open champion Serena Williams followed Nadal into Arthur Ashe Stadium for her first singles match in the tournament since her 2009 tirade at a line judge. She never was challenged by 54th-ranked Bojana Jovanovski of Serbia, needing less than an hour to win 6-1, 6-1.

Williams missed last year’s U.S. Open because of surgery on her right foot after cutting it on glass at a restaurant in Germany in July.