NEW YORK -- It's funny what questions some people will and won't answer.
Take the world's top-ranked tennis player, Caroline Wozniacki.
Her boyfriend? Sure, she's been seeing Rory McIlroy of late.
Her new coach? Well, that, Wozniacki insists, must remain a mystery.
Wozniacki opened her latest quest for her first Grand Slam title with a 6-3, 6-1 victory over Nuria Llagostera Vives of Spain on Tuesday. It was a drama-free afternoon in Arthur Ashe Stadium that left the most interesting stuff for the post-match interview.
How were things going with McIlroy, golf's reigning U.S. Open champion whom she started dating this summer?
"You know, he has something I'm looking for and I have something he's looking for," she said. "He wants to be No. 1. So it's good to have something on each other."
Does the No. 1 ranking, when it's not accompanied by a major, feel like a burden or honor?
"I'm trying to stay up there as long as possible, and it doesn't really matter what people are saying," she said.
And why not end the suspense and tell us who that new coach of yours is?
"Yeah, well, I have to respect him, as well," she said. "So if he wants to be in the background and not have his name out, I have to respect that."
Though she's refusing to name names, Wozniacki is clearly looking for another gear and a few more weapons as she tries to add to a resume that includes 46 of the last 47 weeks at No. 1 but no major championships and only one trip to a Grand Slam final -- two years ago at the U.S. Open, when she lost to Kim Clijsters.
She had what some viewed as a rough summer, losing her first match at both Toronto and Cincinnati -- considered key leadups to the year's last Grand Slam. But last week, she won for the fourth straight year at New Haven, and suddenly, the critics seem more like alarmists.
"I know that I'm back on track," she said. "I know that everyone has to write their stories, but I think we should move on. Ask me about something else, something more interesting."
There wasn't much interesting about this match, except maybe for the observation that Wozniacki didn't need to bring out any new weapons to defeat Llagostera Vives, the diminutive counterpuncher ranked 125th and playing her first singles match on the U.S. Open main show court.
This was typical Wozniacki -- steady groundstrokes and long points, made longer on a surface that players say has been playing slower this year.
On the men's side, top-seeded Novak Djokovic took a 6-0, 5-1 lead in his first-round match against Ireland's Conor Niland before Niland retired because of food poisoning.
It wasn't much of a test for the top-seeded Djokovic, who pulled out with an ailing shoulder while trailing in the second set of the Cincinnati Masters final on Aug. 21.
In his first match since, Djokovic won the first seven games, then after Niland won his single game, Djokovic tore off 16 points in a row. Djokovic moved to 58-2 on the year and this might have been the easiest of them all.
Rafael Nadal opened defense of his U.S. Open title with a tougher-than-expected struggle Tuesday night -- a 6-3, 7-6 (1), 7-5 victory over 98th-ranked Andrey Golubev of Kazakhstan.
Elsewhere on the second day, No. 28-seeded woman Serena Williams dominated in a 6-1, 6-1 victory over Bojana Jovanovski of Serbia.