Injury? What injury? Lindsay Davenport showed no signs of the shoulder and arm problems she brought to the U.S. Open, beating Jelena Kostanic of Croatia 6-0, 6-0 Thursday to reach the third round.

It was the first love-and-love match — a "double bagel" in tennis terms — at the U.S. Open since 2002, when Venus Williams beat Mirjana Lucic by that score in the first round.

"Some days, everything just seems to be working," said Davenport, the 1998 champion and seeded 10th this year. "These days don't happen that often, so you have to be happy when they come your way."

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Former U.S. Open champions Justine Henin-Hardenne and Svetlana Kuznetsova also faced little resistance in the second round. Second-seeded Rafael Nadal faced a tougher test in beating Luis Horna 6-4, 4-6, 6-4, 6-2

The second-seeded Henin-Hardenne stopped Vania King 6-1, 6-2 while Kuznetsova defeated 16-year-old American Lauren Albanese 6-1, 6-1 .

Despite her loss at Louis Armstrong Stadium, King had an engagement at Arthur Ashe Stadium: The 17-year-old American was to sing "America the Beautiful" before the night session.

"I'm really nervous," King said. "I don't know if I'll be more nervous for that than my match."

Andre Agassi was set to play in the evening, and again it could be his final match as a pro. He faced No. 8 Marcos Baghdatis, two days after getting a cortisone shot for an ailing back.

"The inflammation was pretty bad, and I just don't want to go off the court limping," Agassi told USA Network. "It's not what I want to do."

While Davenport was enjoying her breakfast bagels, a crowd formed outside the fence at the practice courts to watch the 36-year-old Agassi warm up.

When he wrapped up, Agassi made a teenager's morning wait worth it, signing the boy's forehead with a Sharpie.

Former Open champion Andy Roddick said he expected a game effort from Agassi.

"I've never had a cortisone shot, but from what I've heard, you feel like you can run through walls," Roddick said. "He's been playing through that pain for a couple of years now, so I think he's used to it."

Davenport didn't face a break point, compiled 11, and produced a 24-2 edge in winners. The match took all of 40 minutes.

"I knew I had to come back tomorrow again and play, so I was trying to get out of here relatively fast. Not that fast," said Davenport, who quit during the final of a hard-court tuneup in New Haven, Conn., last weekend because of fatigue and soreness in her right arm.

In other women's matches Thursday, No. 4 Elena Dementieva topped Emma Laine 6-4, 6-0, No. 7 Patty Schnyder beat Sofia Arvidsson 6-3, 7-5 and No. 9 Nicole Vaidisova topped Alina Jidkova 6-2, 3-6, 6-3. On the men's side, No. 6 Tommy Robredo beat Lee Hyung-taik 3-6, 6-3, 6-4, 6-1.

On Wednesday night, Roddick took one final whack, trying to knock a ball completely out of Ashe Stadium. That's the tradition at the U.S. Open — the winner autographs three balls, then hits them into the crowd. So what if the birthday boy reached only halfway up the top deck?

Roddick finished off a full day of tennis by showing fans that, yes, he's fully focused. He also answered the question that nontennis fans wondered about: Is he going out with Maria Sharapova?

"We're not dating. I've said it a million times already," Roddick said. "We're friendly. We're in the same places. I think she's a great girl. We'll talk. That's about it."

Before Roddick beat Kristian Pless 6-3, 7-6 (3), 6-3, Sharapova played on the same court and beat Michaella Krajicek 6-3, 6-0.

"I probably saw a total of four points in the match," Roddick said. Breaking into a big smile, he added, "but they were great ones."

Asked whether she bought him a present, Sharapova sounded convincing. Or tried to, at least.

"Is it his birthday? I had no idea," she said. "I really don't talk about my personal life. And when two tennis players know each other and are friends, and are known around the world, people are going to talk. That's exactly what's happening."

The 24-year-old Roddick was among several former Open champions to win Wednesday: Roger Federer, Serena Williams, Martina Hingis, Lleyton Hewitt and Marat Safin also advanced.

Top-seeded Amelie Mauresmo, No. 2 Rafael Nadal and No. 5 James Blake moved on, too.