It's only getting worse for Wozniacki

NEW YORK -- Caroline Wozniacki, for all her weaknesses (yes, Rory McIlroy, you're on that list), has been a stellar player here at the U.S. Open.

Three years ago, this year's No. 9 seed made the final, losing to Kim Clijsters. The last two visits to New York brought her all the way to the semifinals. So what to make of Tuesday night's shocker?

Wozniacki lost in the first round to Irina-Camelia Begu 6-2, 6-2. Begu, a 22-year-old from Romania, is ranked No. 96 among WTA players.

It was the first time the 22-year-old Dane has gone out in the first round of a major since her very first Grand Slam appearance, at Roland Garros in 2007.

Wozniacki, who came in with a right knee injury, was visited by a trainer at length in the second set. She retired from her semifinal match last week in New Haven, ending a streak of 20 match wins in that event.

"You always want to go in and do your best no matter what's happening out there," Wozniacki said later. "I tried. I didn't succeed. I didn't play particularly well, made too many errors.

"It's unfortunate because it's a huge tournament, a tournament you want to play well in."

It was the first U.S. Open main-draw victory for Begu, who had previously reached to clay-court semifinals this year. Begu extended No. 1-ranked and eventual bronze medalist Victoria Azarenka to three sets in the first round of the Olympics.

American double(s) upset: Jack Sock and Steve Johnson stunned the No. 1-seeded doubles team of Daniel Nestor and Max Mirnyi after losing the first set 6-1. The final score was 1-6, 7-6 (4), 6-2. Sock is the reigning mixed doubles champion here after pairing with Melanie Oudin. He is also the 2010 junior singles champion. Johnson, a 22-year-old from Orange County, Calif., reached the doubles semifinals in Washington, D.C., with partner Drew Courtney.

Earlier, brothers Christian and Ryan Harrison beat the No. 4-seeded Polish team of Mariusz Fyrstenberg and Marcin Matkowski 7-6 (3), 2-6, 7-6 (7). Christian, 18, and Ryan, 20, showed experience far beyond their ages in that final tiebreaker.

Taking the right steps: Major joint surgery -- as Juan Martin del Potro will tell you -- can be a terrifying proposition.

Last June, doctors carved into Sam Querrey's right elbow and, as recently as April, his ranking had fallen out of the top 100. It has taken more than year for him to return to his high standard.

The first real sign, oddly enough, was a loss in the third round at Wimbledon. Querrey and Marin Cilic went at it for 5 hours, 31 minutes, with the Croatian prevailing 17-15 in the fifth set. It was the second-longest match ever played at the All England Club.

American hard courts always have been conducive to the native Californian's big game and, sure enough, he has come alive this summer. He won his seventh career title in Los Angeles and reached the semifinals at Washington and Winston-Salem.

Tuesday was another step for Querrey, who survived an early scare against Yen-Hsun Lu before winning 6-7 (4), 6-4, 6-4, 7-5.

Querrey always has been a formidable presence in the smaller tournaments, but one of his goals has been to improve his efforts in the Grand Slams. His deepest advancement previously was the fourth round, on three occasions. He has done it twice here at the National Tennis Center, in 2008 and 2010. Maybe it's an even-year thing.

It will be difficult to match this year, since his potential third-round opponent would be No. 6 seed Tomas Berdych.

Not so fast, Milos: Last year he ascended the tennis ladder with dizzying swiftness. This season of expectation, however, has seen a minor sophomore slump for Milos Raonic.

His 2011 Grand Slam debut in Australia (as a qualifier) resulted in a surprising fourth-round appearance. This year? The 21-year-old Canadian was knocked out in the third round at the Australian Open and Roland Garros and the second round at Wimbledon and the Olympics.

On Monday, Raonic found himself trailing Santiago Giraldo by two sets to one and down a break in the fourth. Somehow he dug out, winning 6-3, 4-6, 3-6, 6-4, 6-4 in a raucous atmosphere out on Court 11. The match ran 3 hours, 25 minutes -- and was Raonic's very first U.S. Open main draw victory.

"I haven't even had time to think about that," he said afterward. "But now that you mention it, that's nice.

"It was not looking even in my own eyes at that point like the best situation, but I just made the most of it. Just happy with the outcome. Everything else I've got to hope gets better in the next round."

Top women's seeds overlooked: On Monday, when the USTA communications folks asked how many media folks were interested in interviewing the No. 1 seed, there were few takers. Victoria Azarenka fielded questions in the relative obscurity of Interview Room No. 2.

Tuesday, the No. 2 seed won 6-1, 6-1 and it didn't make much of a sound, either. Agnieszka Radwanska scalded Russia's Nina Bratchikova and seems to have fairly clear sailing until a potential meeting with Dominika Cibulkova in the fourth round.

Kerb service: Watch out for Angelique Kerber.

She's seeded No. 6 here (who knew?) and the German destroyed Anne Keothavong 6-2, 6-0 in a scant 54 minutes. This was her WTA-leading 54th match win of the year and consider this: In her first 15 Grand Slam appearances, Kerber was 7-15. Her cumulative record in the past four majors is now 18-4.

And don't forget, Kerber reached the semifinals here a year ago. She could have a clean run to the quarterfinals, where she might meet No. 2 seed Radwanska.