Nadal has shaky start to US Open title defense

? Rafael Nadal’s first match as defending U.S. Open champ 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 Open title. 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 98th-ranked 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. And Nadal expended a lot more energy Tuesday than Novak Djokovic, who overtook the Spaniard at No. 1 in the rankings last month.

Indeed, it didn’t take too long to see that Djokovic’s right shoulder is feeling fine. He began his first-round match with a 121 mph service winner. Four points later, he closed that game with a 120 mph ace. He whipped forehands exactly where he wanted them. He returned well, too.

Playing his first match since Aug. 21, when he quit because of a sore and tired shoulder, the top-seeded Djokovic began setting aside any questions about his fitness for Flushing Meadows, building a 6-0, 5-1 lead before 197th-ranked qualifier Conor Niland of Ireland stopped after 44 minutes. Niland had food poisoning.

The 24-year-old Serb improved to 58-2 with nine titles in 2011, including at Wimbledon and the Australian Open. Djokovic is on his way to compiling one of the greatest seasons in tennis history, particularly if he can earn his first championship at the U.S. Open, where in the past four years he’s lost twice in the final and twice in the semifinals.

Day 2 of the tournament also included a second consecutive first-round departure from the U.S. Open by the sixth-seeded French Open champion Li Na. Since becoming China’s first major singles champion at Paris in June, Li has gone 5-6, exiting in the second round at Wimbledon, then losing 6-2, 7-5 to 53rd-ranked Simona Halep of Romania on Tuesday.

It’s the first time in 40 years that none of the women’s champions at a season’s first three Grand Slam tournaments reached the second round at the U.S. Open. Wimbledon champion Petra Kvitova lost her first-round match Monday, while Australian Open champion Kim Clijsters withdrew because of a stomach muscle injury.

The active leader for women’s Grand Slam titles, Serena Williams, followed Nadal in Arthur Ashe Stadium on Tuesday night.

Earlier, top-seeded Caroline Wozniacki — ranked No. 1 for most of the past year but still in search of Grand Slam trophy No. 1 — defeated 125th-ranked Nuria Llagostera Vives of Spain 6-3, 6-1.